Method and device for transmitting signal based on determination of starting RB index of RO in wireless communication system

ABSTRACT

A method and a device for transmitting/receiving a signal in a wireless communication system, according to one embodiment of the present invention, perform a two-step or four-step random access procedure, and monitor a PDCCH according to a DRX configuration, wherein the PRACH transmitted in the random access procedure is transmitted on a specific RO from among a plurality of ROs, and a starting RB index of the specific RO can be determined on the basis of (i) the lowest RB index of an RB set including the specific RO, (ii) the starting RB index of an RO positioned at the lowest frequency, and (iii) the lowest RB index of an RB set including the RO positioned at the lowest frequency.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/KR2020/013372, filed on Sep. 29, 2020, which claims the benefit ofU.S. Provisional Application No. 63/069,692, filed on Aug. 24, 2020,U.S. Provisional Application No. 63/067,865, filed on Aug. 19, 2020,U.S. Provisional Application No. 63/067,294, filed on Aug. 18, 2020,U.S. Provisional Application No. 63/034,975, filed on Jun. 4, 2020,Korean Application No. 10-2020-0067924, filed on Jun. 4, 2020, KoreanApplication No. 10-2020-0042502, filed on Apr. 8, 2020, KoreanApplication No. 10-2019-0142315, filed on Nov. 8, 2019, KoreanApplication No. 10-2019-0123439, filed on Oct. 4, 2019, and KoreanApplication No. 10-2019-0122707, filed on Oct. 3, 2019. The disclosuresof the prior applications are incorporated by reference in theirentirety.

TECHNICAL FIELD

The present disclosure relates to a method and apparatus for use in awireless communication system.

BACKGROUND

Generally, a wireless communication system is developing to diverselycover a wide range to provide such a communication service as an audiocommunication service, a data communication service and the like. Thewireless communication is a sort of a multiple access system capable ofsupporting communications with multiple users by sharing availablesystem resources (e.g., bandwidth, transmit power, etc.). For example,the multiple access system may include one of code division multipleaccess (CDMA) system, frequency division multiple access (FDMA) system,time division multiple access (TDMA) system, orthogonal frequencydivision multiple access (OFDMA) system, single carrier frequencydivision multiple access (SC-FDMA) system, and the like.

SUMMARY

The object of the present disclosure is to provide a method andapparatus for performing a random access procedure efficiently in awireless communication system.

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present disclosure are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present disclosure could achieve will be more clearlyunderstood from the following detailed description.

The present disclosure provides a method and apparatus for transmittingand receiving a signal in a wireless communication system.

In one aspect of the present disclosure, provided herein is a method fortransmitting and receiving signals by a user equipment (UE) operating ina wireless communication system, including performing a random accesschannel (RACH) procedure, after performing the RACH procedure,monitoring a physical downlink control channel (PDCCH) for an onduration based on a configured DRX operation, and starting an inactivitytimer and staying awake based on the successfully received PDCCH for theon duration, wherein, during the RACH procedure, a physical randomaccess channel (PRACH) may be transmitted on a specific PRACH occasion(RO) among a plurality of ROs, wherein a starting Resource Block (RB)index of the specific RO may be determined based on (i) a lowest RBindex of an RB set including the specific RO, (ii) a starting RB indexof an RO positioned at a lowest frequency, and (iii) a lowest RB indexof an RB set including the RO positioned at the lowest frequency.

In another aspect of the present disclosure, provided herein is a userequipment (UE) for transmitting and receiving signals in a wirelesscommunication system, including at least one transceiver, at least oneprocessor, and at least one memory operatively coupled to the at leastone processor and configured to store instructions that, when executed,cause the at least one processor to perform specific operations, whereinthe specific operations may include performing a random access channel(RACH) procedure, after performing the RACH procedure, monitoring aphysical downlink control channel (PDCCH) for an on duration based on aconfigured DRX operation, and starting an inactivity timer and stayingawake based on the successfully received PDCCH for the on duration,wherein, during the RACH procedure, a physical random access channel(PRACH) may be transmitted on a specific PRACH occasion (RO) among aplurality of ROs, wherein a starting Resource Block (RB) index of thespecific RO may be determined based on (i) a lowest RB index of an RBset including the specific RO, (ii) a starting RB index of an ROpositioned at a lowest frequency, and (iii) a lowest RB index of an RBset including the RO positioned at the lowest frequency.

In another aspect of the present disclosure, provided herein is anapparatus for a user equipment (UE), including at least one processor,and at least one computer memory operatively coupled to the at least oneprocessor and configured to cause, when executed, the at least oneprocessor to perform operations, the operations including performing arandom access channel (RACH) procedure, after performing the RACHprocedure, monitoring a physical downlink control channel (PDCCH) for anon duration based on a configured DRX operation, and starting aninactivity timer and staying awake based on the successfully receivedPDCCH for the on duration, wherein, during the RACH procedure, aphysical random access channel (PRACH) may be transmitted on a specificPRACH occasion (RO) among a plurality of ROs, wherein a startingResource Block (RB) index of the specific RO may be determined based on(i) a lowest RB index of an RB set including the specific RO, (ii) astarting RB index of an RO positioned at a lowest frequency, and (iii) alowest RB index of an RB set including the RO positioned at the lowestfrequency.

In another aspect of the present disclosure, provided herein is acomputer-readable storage medium including at least one computer programthat causes at least one processor to perform operations, wherein theoperations may include performing a random access channel (RACH)procedure, after performing the RACH procedure, monitoring a physicaldownlink control channel (PDCCH) for an on duration based on aconfigured DRX operation, and starting an inactivity timer and stayingawake based on the successfully received PDCCH for the on duration,wherein, during the RACH procedure, a physical random access channel(PRACH) may be transmitted on a specific PRACH occasion (RO) among aplurality of ROs, wherein a starting Resource Block (RB) index of thespecific RO may be determined based on (i) a lowest RB index of an RBset including the specific RO, (ii) a starting RB index of an ROpositioned at a lowest frequency, and (iii) a lowest RB index of an RBset including the RO positioned at the lowest frequency.

In the methods and apparatuses, a value of the start RB index of thespecific RO may be obtained by adding a value of the lowest RB index ofthe RB set including the specific RO and an offset value, wherein theoffset value may be obtained by subtracting a value of the lowest RBindex of the RB set including the RO positioned at the lowest frequencyfrom a value of the starting RB index of the RO positioned at the lowestfrequency.

In the methods and apparatuses, the plurality of ROs may be included inuplink RB sets, respectively, one for each of the uplink RB sets.

In the methods and apparatuses, the uplink RB sets may be included in anuplink active Bandwidth Part (BWP).

In the methods and apparatuses, despite UE-specific guard bandinformation for each of the uplink RB sets, the plurality of ROs may beconfigured on a basis that the respective uplink RB sets are configuredbased on nominal guard band information.

The communication apparatus may include an autonomous driving vehiclecommunicable with at least a UE, a network, and another autonomousdriving vehicle other than the communication apparatus.

The above-described aspects of the present disclosure are only some ofthe preferred embodiments of the present disclosure, and variousembodiments reflecting the technical features of the present disclosuremay be derived and understood from the following detailed description ofthe present disclosure by those skilled in the art.

According to an embodiment of the present disclosure, a communicationapparatus may perform a random access procedure more efficiently in adifferent way from the prior art.

It will be appreciated by persons skilled in the art that the effectsthat can be achieved with the present disclosure are not limited to whathas been particularly described hereinabove and other advantages of thepresent disclosure will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a radio frame structure.

FIG. 2 illustrates a resource grid during the duration of a slot.

FIG. 3 illustrates a self-contained slot structure.

FIG. 4 illustrates an acknowledgment/negative acknowledgment (ACK/NACK)transmission process.

FIGS. 5A and 5B illustrate a wireless communication system supporting anunlicensed band.

FIG. 6 illustrates an exemplary method of occupying resources in anunlicensed band.

FIGS. 7 and 8 are flowcharts illustrating channel access procedures(CAPs) for signal transmission in an unlicensed band.

FIG. 9 illustrates a resource block (RB) interlace.

FIGS. 10A to 11B are diagrams illustrating a signal flow for a randomaccess procedure;

FIGS. 12 to 18 is a diagram illustrating uplink (UL) channeltransmission according to the embodiments of the present disclosure.

FIGS. 19 to 22 illustrate devices according to an embodiment of thepresent disclosure.

DETAILED DESCRIPTION

The following technology may be used in various wireless access systemssuch as code division multiple access (CDMA), frequency divisionmultiple access (FDMA), time division multiple access (TDMA), orthogonalfrequency division multiple access (OFDMA), single carrier frequencydivision multiple access (SC-FDMA), and so on. CDMA may be implementedas a radio technology such as universal terrestrial radio access (UTRA)or CDMA2000. TDMA may be implemented as a radio technology such asglobal system for mobile communications (GSM)/general packet radioservice (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA maybe implemented as a radio technology such as institute of electrical andelectronics engineers (IEEE) 802.11 (wireless fidelity (Wi-Fi)), IEEE802.16 (worldwide interoperability for microwave access (WiMAX)), IEEE802.20, evolved UTRA (E-UTRA), and so on. UTRA is a part of universalmobile telecommunications system (UMTS). 3rd generation partnershipproject (3GPP) long term evolution (LTE) is a part of evolved UMTS(E-UMTS) using E-UTRA, and LTE-advanced (LTE-A) is an evolution of 3GPPLTE. 3GPP new radio or new radio access technology (NR) is an evolvedversion of 3GPP LTE/LTE-A.

For clarity of description, the present disclosure will be described inthe context of a 3GPP communication system (e.g., LTE and NR), whichshould not be construed as limiting the spirit of the presentdisclosure. LTE refers to a technology beyond 3GPP TS 36.xxx Release 8.Specifically, the LTE technology beyond 3GPP TS 36.xxx Release 10 iscalled LTE-A, and the LTE technology beyond 3GPP TS 36.xxx Release 13 iscalled LTE-A pro. 3GPP NR is the technology beyond 3GPP TS 38.xxxRelease 15. LTE/NR may be referred to as a 3GPP system. “xxx” specifiesa technical specification number. LTE/NR may be generically referred toas a 3GPP system. For the background technology, terminologies,abbreviations, and so on as used herein, refer to technicalspecifications published before the present disclosure. For example, thefollowing documents may be referred to.

3GPP NR

-   -   38.211: Physical channels and modulation    -   38.212: Multiplexing and channel coding    -   38.213: Physical layer procedures for control    -   38.214: Physical layer procedures for data    -   38.300: NR and NG-RAN Overall Description    -   38.331: Radio Resource Control (RRC) protocol specification

FIG. 1 illustrates a radio frame structure used for NR.

In NR, UL and DL transmissions are configured in frames. Each radioframe has a length of 10 ms and is divided into two 5-ms half-frames.Each half-frame is divided into five 1-ms subframes. A subframe isdivided into one or more slots, and the number of slots in a subframedepends on a subcarrier spacing (SCS). Each slot includes 12 or 14OFDM(A) symbols according to a cyclic prefix (CP). When a normal CP isused, each slot includes 14 OFDM symbols. When an extended CP is used,each slot includes 12 OFDM symbols. A symbol may include an OFDM symbol(or a CP-OFDM symbol) and an SC-FDMA symbol (or a discrete Fouriertransform-spread-OFDM (DFT-s-OFDM) symbol).

Table 1 exemplarily illustrates that the number of symbols per slot, thenumber of slots per frame, and the number of slots per subframe varyaccording to SCSs in a normal CP case.

TABLE 1 SCS (15*2{circumflex over ( )}u) N_(symb) ^(slot) N_(slot)^(frame, u) N_(slot) ^(subframe, u)  15 KHz (u = 0) 14 10 1  30 KHz (u= 1) 14 20 2  60 KHz (u = 2) 14 40 4 120 KHz (u = 3) 14 80 8 240 KHz (u= 4) 14 160 16 * N_(symb) ^(slot): number of symbols in a slot *N_(slot) ^(frame, u): number of slots in a frame * N_(slot)^(subframe, u): number of slots in a subframe

Table 2 illustrates that the number of symbols per slot, the number ofslots per frame, and the number of slots per subframe vary according toSCSs in an extended CP case.

TABLE 2 SCS (15*2{circumflex over ( )}u) N_(symb) ^(slot) N_(slot)^(frame, u) N_(slot) ^(subframe, u) 60 KHz (u = 2) 12 40 4

In the NR system, different OFDM(A) numerologies (e.g., SCSs, CPlengths, and so on) may be configured for a plurality of cellsaggregated for one UE. Accordingly, the (absolute time) duration of atime resource (e.g., a subframe, a slot, or a transmission time interval(TTI)) (for convenience, referred to as a time unit (TU)) composed ofthe same number of symbols may be configured differently between theaggregated cells.

In NR, various numerologies (or SCSs) may be supported to supportvarious 5th generation (5G) services. For example, with an SCS of 15kHz, a wide area in traditional cellular bands may be supported, whilewith an SCS of 30 kHz or 60 kHz, a dense urban area, a lower latency,and a wide carrier bandwidth may be supported. With an SCS of 60 kHz orhigher, a bandwidth larger than 24.25 kHz may be supported to overcomephase noise.

An NR frequency band may be defined by two types of frequency ranges,FR1 and FR2. FR1 and FR2 may be configured as described in Table 3below. FR2 may be millimeter wave (mmW).

TABLE 3 Frequency Range Corresponding frequency designation rangeSubcarrier Spacing FR1  450 MHz-7125 MHz 15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

FIG. 2 illustrates a resource grid during the duration of one slot.

A slot includes a plurality of symbols in the time domain. For example,one slot includes 14 symbols in a normal CP case and 12 symbols in anextended CP case. A carrier includes a plurality of subcarriers in thefrequency domain. A resource block (RB) may be defined by a plurality of(e.g., 12) consecutive subcarriers in the frequency domain. A pluralityof RB interlaces (simply, interlaces) may be defined in the frequencydomain. Interlace m∈{0, 1, . . . , M−1} may be composed of (common) RBs{m, M+m, 2M+m, 3M+m, . . . }. M denotes the number of interlaces. Abandwidth part (BWP) may be defined by a plurality of consecutive(physical) RBs ((P)RBs) in the frequency domain and correspond to onenumerology (e.g., SCS, CP length, and so on). A carrier may include upto N (e.g., 5) BWPs. Data communication may be conducted in an activeBWP, and only one BWP may be activated for one UE. Each element in aresource grid may be referred to as a resource element (RE), to whichone complex symbol may be mapped.

In a wireless communication system, a UE receives information from a BSin downlink (DL), and the UE transmits information to the BS in uplink(UL). The information exchanged between the BS and UE includes data andvarious control information, and various physical channels/signals arepresent depending on the type/usage of the information exchangedtherebetween. A physical channel corresponds to a set of resourceelements (REs) carrying information originating from higher layers. Aphysical signal corresponds to a set of REs used by physical layers butdoes not carry information originating from the higher layers. Thehigher layers include a medium access control (MAC) layer, a radio linkcontrol (RLC) layer, a packet data convergence protocol (PDCP) layer, aradio resource control (RRC) layer, and so on.

DL physical channels include a physical broadcast channel (PBCH), aphysical downlink shared channel (PDSCH), and a physical downlinkcontrol channel (PDCCH). DL physical signals include a DL referencesignal (RS), a primary synchronization signal (PSS), and a secondarysynchronization signal (SSS). The DL RS includes a demodulationreference signal (DM-RS), a phase tracking reference signal (PT-RS), anda channel state information reference signal (CSI-RS). UL physicalchannel include a physical random access channel (PRACH), a physicaluplink shared channel (PUSCH), and a physical uplink control channel(PUCCH). UL physical signals include a UL RS. The UL RS includes aDM-RS, a PT-RS, and a sounding reference signal (SRS).

FIG. 3 illustrates a structure of a self-contained slot.

In the NR system, a frame has a self-contained structure in which a DLcontrol channel, DL or UL data, a UL control channel, and the like mayall be contained in one slot. For example, the first N symbols(hereinafter, DL control region) in the slot may be used to transmit aDL control channel, and the last M symbols (hereinafter, UL controlregion) in the slot may be used to transmit a UL control channel. N andM are integers greater than or equal to 0. A resource region(hereinafter, a data region) that is between the DL control region andthe UL control region may be used for DL data transmission or UL datatransmission. For example, the following configuration may beconsidered. Respective sections are listed in a temporal order.

In the present disclosure, a base station (BS) may be, for example, agNode B (gNB).

DL Physical Channel/Signal

(1) PDSCH

A PDSCH carries DL data (e.g., DL-shared channel transport block (DL-SCHTB)). The TB is coded into a codeword (CW) and then transmitted afterscrambling and modulation processes. The CW includes one or more codeblocks (CBs). One or more CBs may be grouped into one code block group(CBG). Depending on the configuration of a cell, the PDSCH may carry upto two CWs. Scrambling and modulation may be performed for each CW, andmodulation symbols generated from each CW may be mapped to one or morelayers. Each layer may be mapped to resources together with a DMRS afterprecoding and transmitted on a corresponding antenna port. The PDSCH maybe dynamically scheduled by a PDCCH (dynamic scheduling). Alternatively,the PDSCH may be semi-statically scheduled based on higher layer (e.g.,RRC) signaling (and/or Layer 1 (L1) signaling (e.g., PDCCH)) (configuredscheduling (CS)). Therefore, in the dynamic scheduling, PDSCHtransmission is accompanied by the PDCCH, whereas in the CS, PDSCHtransmission may not be accompanied by the PDCCH. The CS may includesemi-persistent scheduling (SPS).

(2) PDCCH

A PDCCH carries Downlink Control Information (DCI). For example, thePDCCH (i.e., DCI) may carry: transmission formats and resourceallocation of a DL-SCH; frequency/time resource allocation informationon an uplink shared channel (UL-SCH); paging information on a pagingchannel (PCH); system information on a DL-SCH; time/frequency resourceallocation information on a higher layer control message such as arandom access response (RAR) transmitted over a PDSCH; transmit powercontrol commands; and information on activation/deactivation of SPS/CS.Various DCI formats may be provided depending on information in DCI.

Table 4 shows DCI formats transmitted over the PDCCH.

TABLE 4 DCI format Usage 0_0 Scheduling of PUSCH in one cell 0_1Scheduling of one or multiple PUSCH in one cell, or indicating downlinkfeedback information for configured grant PUSCH (CG-DFI) 1_0 Schedulingof PDSCH in one cell 1_1 Scheduling of PDSCH in one cell, and/ortriggering one shot HARQ-ACK codebook feedback 2_0 Notifying a group ofUEs of the slot format, available RB sets, COT duration search space setgroup switching 2_1 Notifying a group of UEs of the PRB(s) and OFDMsymbol(s) be UE may assume no transmission is intended for the UE 2_2Transmission of TPC commands for PUCCH and PUSCH 2_3 Transmission of agroup of TPC commands for SRS transmissions by one or more UEs

DCI format 0_0 may be used to schedule a TB-based (or TB-level) PUSCH,and DCI format 0_1 may be used to schedule a TB-based (or TB-level)PUSCH or a CBG-based (or CBG-level) PUSCH. DCI format 1_0 may be used toschedule a TB-based (or TB-level) PDSCH, and DCI format 1_1 may be usedto schedule a TB-based (or TB-level) PDSCH or a CBG-based (or CBG-level)PDSCH (DL grant DCI). DCI format 0_0/0_1 may be referred to as UL grantDCI or UL scheduling information, and DCI format 1_0/1_1 may be referredto as DL grant DCI or UL scheduling information. DCI format 2_0 may beused to provide dynamic slot format information (e.g., dynamic SFI) tothe UE, and DCI format 2_1 may be used to provide downlink pre-emptioninformation to the UE. UEs defined as one group may be provided with DCIformat 2_0 and/or DCI format 2_1 over a group common PDCCH, which is aPDCCH defined for a group of UEs.

The PDCCH/DCI may include a cyclic redundancy check (CRC), and the CRCmay be masked/scrambled with various identifiers (e.g., radio networktemporary identifier (RNTI)) according to the owner or purpose of thePDCCH. For example, if the PDCCH is for a specific UE, the CRC may bemasked with a cell-RNTI (C-RNTI). If the PDCCH relates to paging, theCRC may be masked with a paging-RNTI (P-RNTI). If the PDCCH relates tosystem information (e.g., system information block (SIB)), the CRC maybe masked with a system information RNTI (SI-RNTI). If the PDCCH relatesto a random access response, the CRC may be masked with a randomaccess-RNTI (RA-RNTI).

Table 5 shows the usage of the PDCCH and transport channels according tothe type of RNTI. Here, the transport channel means a transport channelrelated to data carried by a PDSCH/PUSCH scheduled by the PDCCH.

TABLE 5 RNTI Usage Transport Channel P-RNTI Paging and SystemInformation change notification PCH(Paging Channel) SI-RNTI Broadcast ofSystem Information DL-SCH RA-RNTI Random Access Response DL-SCHTemporary C-RNTI Contention Resolution DL-SCH (when no valid C-RNTI isavailable) Temporary C-RNTI Msg3 transmission UL-SCH C-RNTI,MCS(Modulation Dynamically scheduled unicast transmission UL-SCH andCoding Scheme)-C- RNTI C-RNTI Dynamically scheduled unicast transmissionDL-SCH MCS-C-RNTI Dynamically scheduled unicast transmission DL-SCHC-RNTI Triggering of PDCCH ordered random access N/A CS(ConfiguredScheduling)- Configured scheduled unicast transmission DL-SCH, UL-SCHRNTI (activation, reactivation and retransmission) CS-RNTI Configuredscheduled unicast transmission N/A (deactivation) TPC(Transmit PowerPUCCH power control N/A Control)-PUCCH-RNTI TPC-PUSCH-RNTI PUSCH powercontrol N/A TPC-SRS-RNTI SRS trigger and power control N/AINT(Interruption)-RNTI Indication pre-emption in DL N/A SFI(Slot FormatIndication)- Slot Format Indication on the given cell N/A RNTISP(Semi-persistent)- Activation of Semi-persistent CSI reporting onPUSCH N/A CSI(Channel State Information)-RNTI

For the PDCCH, a fixed modulation scheme may be used (e.g., quadraturephase shift keying (QPSK)). One PDCCH may include 1, 2, 4, 8, or 16control channel elements (CCEs) depending on the aggregation level (AL).One CCE may include 6 resource element groups (REGs), and one REG may bedefined by one OFDMA symbol and one (P)RB.

The PDCCH may be transmitted in a control resource set (CORESET). TheCORESET corresponds to a set of physical resources/parameters used tocarry the PDCCH/DCI within a BWP. For example, the CORESET may include aset of REGs with a given numerology (e.g., SCS, CP length, etc.). TheCORESET may be configured by system information (e.g., MIB) orUE-specific higher layer (e.g., RRC) signaling. For example, thefollowing parameters/information may be used to configure the CORESET.One UE may be configured with one or more CORESETs, and a plurality ofCORESETs may overlap in the time/frequency domain.

-   -   controlResourceSetId: this parameter/information indicates the        identifier (ID) of the CORESET.    -   frequencyDomainResources: this parameter/information indicates        frequency-domain resources of the CORESET. The frequency-domain        resources may be indicated by a bitmap, and each bit corresponds        to an RB group (=6 consecutive RBs). For example, the most        significant bit (MSB) of the bitmap corresponds to the first RB        group in the BWP. An RB group corresponding to a bit with a        value of 1 may be allocated as a frequency-domain resource of        the CORESET.    -   duration: this parameter/information indicates time-domain        resources of the CORESET. The parameter/information duration may        indicate the number of consecutive OFDMA symbols included in the        CORESET. For example, duration has a value of 1-3.    -   cce-REG-MappingType: this parameter/information indicates a        CCE-to-REG mapping type. An interleaved type and a        non-interleaved type may be supported.    -   precoderGranularity: this parameter/information indicates a        precoder granularity in the frequency domain.    -   tci-StatesPDCCH: this parameter/information indicates        information (e.g., TCI-StateID) on a transmission configuration        indication (TCI) state for the PDCCH. The TCI state may be used        to provide a quasi-co-location (QCL) relationship between DL        RS(s) in an RS set (TCI-state) and a PDCCH DMRS port.    -   tci-PresentInDCI: this parameter/information indicates whether a        TCI field is included in DCI.    -   pdcch-DMRS-ScramblingID: this parameter/information indicates        information used for initialization of a PDCCH DMRS scrambling        sequence.

For PDCCH reception, the UE may monitor (e.g., blind decoding) a set ofPDCCH candidates in the CORESET. The PDCCH candidate may mean CCE(s)monitored by the UE for PDCCH reception/detection. PDCCH monitoring maybe performed in one or more CORESETs in an active DL BWP on each activecell in which the PDCCH monitoring is configured. The set of PDCCHcandidates monitored by the UE may be defined as a PDCCH search space(SS) set. The SS set may be classified into a common search space (CSS)set or a UE-specific search space (USS) set.

Table 6 shows PDCCH search spaces.

TABLE 6 Search Space Type RNTI Use Case Type0-PDCCH Common SI-RNTI on aprimary cell Broadcast of System Information Type0A-PDCCH Common SI-RNTIon a primary cell Broadcast of System Information Type1-PDCCH CommonRA-RNTI or TC-RNTI on a primary cell Msg2, Msg4 in RACH Type2-PDCCHCommon P-RNTI on a primary cell Paging System Information changenotification Type3-PDCCH Common INT-RNTI, SFI-RNTI, TPC-PUSCH-RNTI, TPC-Group signaling PUCCH-RNTI, TPC-SRS-RNTI, C-RNTI, MCS- C-RNTI or CS-RNTIUE Specific UE Specific C-RNTI, MCS-C-RNTI or CS-RNTI UE signaling(e.g., PDSCH/PUSCH)

The SS set may be configured by system information (e.g., MIB) orUE-specific higher layer (e.g., RRC) signaling. S (e.g., 10) SS sets orless may be configured in each DL BWP of a serving cell. For example,the following parameters/information may be provided for each SS set.Each SS set may be associated with one CORESET, and each CORESETconfiguration may be associated with one or more SS sets.

-   -   searchSpaceId: this parameter/information indicates the ID of        the SS set.    -   controlResourceSetId: this parameter/information indicates the        CORESET associated with the SS set.    -   monitoringSlotPeriodicityAndOffset: this parameter/information        indicates a PDCCH monitoring periodicity (in a unit of slot) and        a PDCCH monitoring offset (in a unit of slot)    -   monitoringSymbolsWithinSlot: this parameter/information        indicates first OFDMA symbol(s) for PDCCH monitoring in a slot        in which the PDCCH monitoring is configured. The first OFDMA        symbol(s) are indicated by a bitmap, and each bit corresponds to        each OFDMA symbol in the slot. The MSB of the bitmap corresponds        to the first OFDM symbol in the slot. OFDMA symbol(s)        corresponding to bit(s) with a value of 1 corresponds to the        first symbol(s) in the CORESET in the slot.    -   nrofCandidates: this parameter/information indicates the number        of PDCCH candidates (e.g., one of 0, 1, 2, 3, 4, 5, 6, and 8)        for each AL (where AL={1, 2, 4, 8, 16}).    -   searchSpaceType: this parameter/information indicates whether        the SS type is the CSS or USS.    -   DCI format: this parameter/information indicates the DCI format        of a PDCCH candidate.

The UE may monitor PDCCH candidates in one or more SS sets in a slotaccording to the configuration of the CORESET/SS set. An occasion (e.g.,time/frequency resource) to monitor PDCCH candidates is defined as aPDCCH (monitoring) occasion. One or more PDCCH (monitoring) occasionsmay be configured within a slot.

UL Physical Channels/Signals

(1) PUSCH

A PUSCH may carry UL data (e.g., uplink shared channel (UL-SCH)transport block (TB)) and/or uplink control information (UCI). The PUSCHmay be transmitted based on a cyclic prefix orthogonal frequencydivision multiplexing (CP-OFDM) waveform or a discrete Fourier transformspread OFDM (DFT-s-OFDM) waveform. When the PUSCH is transmitted basedon the DFT-s-OFDM waveform, the UE may transmit the PUSCH by applyingtransform precoding. For example, when the transform precoding is notallowed (e.g., when the transform precoding is disabled), the UE maytransmit the PUSCH based on the CP-OFDM waveform. When the transformprecoding is allowed (e.g., when the transform precoding is enabled),the UE may transmit the PUSCH based on the CP-OFDM waveform orDFT-s-OFDM waveform. PUSCH transmission may be dynamically scheduled bya PDCCH (dynamic scheduling) or semi-statically scheduled by higherlayer signaling (e.g., RRC signaling) (and/or Layer 1 (L1) signaling(e.g., PDCCH)) (configured scheduling (CS)). Therefore, in the dynamicscheduling, the PUSCH transmission may be associated with the PDCCH,whereas in the CS, the PUSCH transmission may not be associated with thePDCCH. The CS may include PUSCH transmission based on a Type-1configured grant (CG) and PUSCH transmission based on a Type-2 CG. Forthe Type-1 CG, all parameters for PUSCH transmission may be signaled bythe higher layer. For the Type-2 CG, some parameters for PUSCHtransmission may be signaled by higher layers, and the rest may besignaled by the PDCCH. Basically, in the CS, the PUSCH transmission maynot be associated with the PDCCH.

(2) PUCCH

A PUCCH may carry UCI. The UCI includes the following information.

-   -   Scheduling request (SR): The SR is information used to request a        UL-SCH resource.    -   Hybrid automatic repeat and request acknowledgement) (HARQ-ACK):        The HARQ-ACK is a signal in response to reception of a DL signal        (e.g., PDSCH, SPS release PDCCH, etc.). The HARQ-ACK response        may include positive ACK (ACK), negative ACK (NACK), DTX        (Discontinuous Transmission), or NACK/DTX. The HARQ-ACK may be        interchangeably used with A/N, ACK/NACK, HARQ-ACK/NACK, and the        like. The HARQ-ACK may be generated on a TB/CBG basis.    -   Channel Status Information (CSI): The CSI is feedback        information on a DL channel. The CSI includes a channel quality        indicator (CQI), a rank indicator (RI), a precoding matrix        indicator (PMI), a precoding type indicator (PTI), and so on.

Table 7 shows PUCCH formats. The PUCCH formats may be classifiedaccording to UCI payload sizes/transmission lengths (e.g., the number ofsymbols included in a PUCCH resource) and/or transmission structures.The PUCCH formats may be classified into short PUCCH formats (PUCCHformats 0 and 2) and long PUCCH formats (PUCCH formats 1, 3, and 4)according to the transmission lengths.

TABLE 7 Length in Number PUCCH OFDM symbols of format N_(symb) ^(PUCCH)bits Usage Etc 0 1-2  ≤2 HARQ, SR Sequence selection 1 4-14 ≤2 HARQ,[SR] Sequence modulation 2 1-2  >2 HARQ, CSI, [SR] CP-OFDM 3 4-14 >2HARQ, CSI, [SR] DFT-s-OFDM (no UE multiplexing) 4 4-14 >2 HARQ, CSI,[SR] DFT-s-OFDM (Pre DFT OCC)

(0) PUCCH Format 0 (PF0)

-   -   Supportable UCI payload size: up to K bits (e.g., K=2)    -   Number of OFDM symbols included in one PUCCH: 1 to X symbols        (e.g., X=2)    -   Transmission structure: only a UCI signal is configured with no        DM-RS, and a UCI state is transmitted by selecting and        transmitting one of a plurality of sequences.

(1) PUCCH Format 1 (PF1)

-   -   Supportable UCI payload size: up to K bits (e.g., K=2)    -   Number of OFDM symbols included in one PUCCH: Y to Z symbols        (e.g., Y=4 and Z=14)    -   Transmission structure: UCI and a DM-RS are configured in        different OFDM symbols based on time division multiplexing        (TDM). For the UCI, a specific sequence is multiplied by a        modulation symbol (e.g., QPSK symbol). A cyclic shift/orthogonal        cover code (CS/OCC) is applied to both the UCI and DM-RS to        support code division multiplexing (CDM) between multiple PUCCH        resources (complying with PUCCH format 1) (in the same RB).

(2) PUCCH Format 2 (PF2)

-   -   Supportable UCI payload size: more than K bits (e.g., K=2)    -   Number of OFDM symbols included in one PUCCH: 1 to X symbols        (e.g., X=2)    -   Transmission structure: UCI and a DMRS (DM-RS) are        configured/mapped in/to the same symbol based on frequency        division multiplexing (FDM), and encoded UCI bits are        transmitted by applying only an inverse fast Fourier transform        (IFFT) thereto with no DFT.

(3) PUCCH Format 3 (PF3)

-   -   Supportable UCI payload size: more than K bits (e.g., K=2)    -   Number of OFDM symbols included in one PUCCH: Y to Z symbols        (e.g., Y=4 and Z=14)    -   Transmission structure: UCI and a DMRS are configured/mapped        in/to different symbols based on TDM. Encoded UCI bits are        transmitted by applying a DFT thereto. To support multiplexing        between multiple UEs, an OCC is applied to the UCI, and a CS (or        interleaved frequency division multiplexing (IFDM) mapping) is        applied to the DM-RS before the DFT.

(4) PUCCH Format 4 (PF4 or F4)

-   -   Supportable UCI payload size: more than K bits (e.g., K=2)    -   Number of OFDM symbols included in one PUCCH: Y to Z symbols        (e.g., Y=4 and Z=14)    -   Transmission structure: UCI and a DMRS are configured/mapped        in/to different symbols based on TDM. The DFT is applied to        encoded UCI bits with no multiplexing between UEs.

FIG. 4 illustrates an ACK/NACK transmission process. Referring to FIG. 4, the UE may detect a PDCCH in slot #n. The PDCCH includes DL schedulinginformation (e.g., DCI format 1_0 or DCI format 1_1). The PDCCHindicates a DL assignment-to-PDSCH offset, K0 and a PDSCH-to-HARQ-ACKreporting offset, K1. For example, DCI format 1_0 or DCI format 1_1 mayinclude the following information.

-   -   Frequency domain resource assignment: Indicates an RB set        assigned to a PDSCH.    -   Time domain resource assignment: Indicates K0 and the starting        position (e.g., OFDM symbol index) and length (e.g., the number        of OFDM symbols) of the PDSCH in a slot.    -   PDSCH-to-HARQ feedback timing indicator: Indicates K1.

After receiving a PDSCH in slot #(n+K0) according to the schedulinginformation of slot #n, the UE may transmit UCI on a PUCCH in slot#(n+K1). The UCI includes an HARQ-ACK response to the PDSCH. In the casewhere the PDSCH is configured to carry one TB at maximum, the HARQ-ACKresponse may be configured in one bit. In the case where the PDSCH isconfigured to carry up to two TBs, the HARQ-ACK response may beconfigured in two bits if spatial bundling is not configured and in onebit if spatial bundling is configured. When slot #(n+K1) is designatedas an HARQ-ACK transmission timing for a plurality of PDSCHs, UCItransmitted in slot #(n+K1) includes HARQ-ACK responses to the pluralityof PDSCHs.

1. Wireless Communication System Supporting Unlicensed Band

FIGS. 5A and 5B illustrate an exemplary wireless communication systemsupporting an unlicensed band applicable to the present disclosure.

In the following description, a cell operating in a licensed band(L-band) is defined as an L-cell, and a carrier of the L-cell is definedas a (DL/UL) LCC. A cell operating in an unlicensed band (U-band) isdefined as a U-cell, and a carrier of the U-cell is defined as a (DL/UL)UCC. The carrier/carrier-frequency of a cell may refer to the operatingfrequency (e.g., center frequency) of the cell. A cell/carrier (e.g.,CC) is commonly called a cell.

When a BS and a UE transmit and receive signals on carrier-aggregatedLCC and UCC as illustrated in FIG. 5A, the LCC and the UCC may beconfigured as a primary CC (PCC) and a secondary CC (SCC), respectively.The BS and the UE may transmit and receive signals on one UCC or on aplurality of carrier-aggregated UCCs as illustrated in FIG. 5B. In otherwords, the BS and UE may transmit and receive signals only on UCC(s)without using any LCC. For an SA operation, PRACH, PUCCH, PUSCH, and SRStransmissions may be supported on a UCell.

Signal transmission and reception operations in an unlicensed band asdescribed in the present disclosure may be applied to theafore-mentioned deployment scenarios (unless specified otherwise).

Unless otherwise noted, the definitions below are applicable to thefollowing terminologies used in the present disclosure.

-   -   Channel: a carrier or a part of a carrier composed of a        contiguous set of RBs in which a channel access procedure (CAP)        is performed in a shared spectrum.    -   Channel access procedure (CAP): a procedure of assessing channel        availability based on sensing before signal transmission in        order to determine whether other communication node(s) are using        a channel. A basic sensing unit is a sensing slot with a        duration of T_(sl)=9 us. The BS or the UE senses the slot during        a sensing slot duration. When power detected for at least 4 us        within the sensing slot duration is less than an energy        detection threshold X_(thresh), the sensing slot duration T_(sl)        is be considered to be idle. Otherwise, the sensing slot        duration T_(sl) is considered to be busy. CAP may also be called        listen before talk (LBT).    -   Channel occupancy: transmission(s) on channel(s) from the BS/UE        after a CAP.    -   Channel occupancy time (COT): a total time during which the        BS/UE and any BS/UE(s) sharing channel occupancy performs        transmission(s) on a channel after a CAP. Regarding COT        determination, if a transmission gap is less than or equal to 25        us, the gap duration may be counted in a COT. The COT may be        shared for transmission between the BS and corresponding UE(s).    -   DL transmission burst: a set of transmissions without any gap        greater than 16 us from the BS. Transmissions from the BS, which        are separated by a gap exceeding 16 us are considered as        separate DL transmission bursts. The BS may perform        transmission(s) after a gap without sensing channel availability        within a DL transmission burst.    -   UL transmission burst: a set of transmissions without any gap        greater than 16 us from the UE. Transmissions from the UE, which        are separated by a gap exceeding 16 us are considered as        separate UL transmission bursts. The UE may perform        transmission(s) after a gap without sensing channel availability        within a DL transmission burst.    -   Discovery burst: a DL transmission burst including a set of        signal(s) and/or channel(s) confined within a window and        associated with a duty cycle. The discovery burst may include        transmission(s) initiated by the BS, which includes a PSS, an        SSS, and a cell-specific RS (CRS) and further includes a        non-zero power CSI-RS. In the NR system, the discover burst        includes may include transmission(s) initiated by the BS, which        includes at least an SS/PBCH block and further includes a        CORESET for a PDCCH scheduling a PDSCH carrying SIB1, the PDSCH        carrying SIB1, and/or a non-zero power CSI-RS.

FIG. 6 illustrates a resource occupancy method in a U-band. According toregional regulations for U-bands, a communication node in the U-bandneeds to determine whether a channel is used by other communicationnode(s) before transmitting a signal. Specifically, the communicationnode may perform carrier sensing (CS) before transmitting the signal soas to check whether the other communication node(s) perform signaltransmission. When the other communication node(s) perform no signaltransmission, it is said that clear channel assessment (CCA) isconfirmed. When a CCA threshold is predefined or configured by higherlayer signaling (e.g., RRC signaling), the communication node maydetermine that the channel is busy if the detected channel energy ishigher than the CCA threshold. Otherwise, the communication node maydetermine that the channel is idle. The Wi-Fi standard (802.11ac)specifies a CCA threshold of −62 dBm for non-Wi-Fi signals and a CCAthreshold of −82 dBm for Wi-Fi signals. When it is determined that thechannel is idle, the communication node may start the signaltransmission in a UCell. The sires of processes described above may bereferred to as Listen-Before-Talk (LBT) or a channel access procedure(CAP). The LBT, CAP, and CCA may be interchangeably used in thisdocument.

Specifically, for DL reception/UL transmission in a U-band, at least oneof the following CAP methods to be described below may be employed in awireless communication system according to the present disclosure.

DL Signal Transmission Method in U-Band

The BS may perform one of the following U-band access procedures (e.g.,CAPs) for DL signal transmission in a U-band.

(1) Type 1 DL CAP Method

In the Type 1 DL CAP, the length of a time duration spanned by sensingslots sensed to be idle before transmission(s) may be random. The Type 1DL CAP may be applied to the following transmissions:

-   -   Transmission(s) initiated by the BS including (i) a unicast        PDSCH with user plane data or (ii) a unicast PDCCH scheduling        user plane data in addition to the unicast PDSCH with user plane        data, or    -   Transmission(s) initiated by the BS including (i) a discovery        burst only or (ii) a discovery burst multiplexed with        non-unicast information.

FIG. 7 is a flowchart illustrating CAP operations performed by a BS totransmit a DL signal in a U-band.

Referring to FIG. 7 , the BS may sense whether a channel is idle forsensing slot durations of a defer duration T_(d). Then, if a counter Nis zero, the BS may perform transmission (S1234). In this case, the BSmay adjust the counter N by sensing the channel for additional sensingslot duration(s) according to the following steps:

-   -   Step 1) (S1220) The BS sets N to N_(init) (N=N_(init)), where        N_(init) is a random number uniformly distributed between 0 and        CW_(p). Then, step 4 proceeds.    -   Step 2) (S1240) If N>0 and the BS determines to decrease the        counter, the BS sets N to N−1 (N=N−1).    -   Step 3) (S1250) The BS senses the channel for the additional        sensing slot duration. If the additional sensing slot duration        is idle (Y), step 4 proceeds. Otherwise (N), step 5 proceeds.    -   Step 4) (S1230) If N=0 (Y), the BS terminates the CAP (S1232).        Otherwise (N), step 2 proceeds.    -   Step 5) (S1260) The BS senses the channel until either a busy        sensing slot is detected within an additional defer duration        T_(d) or all the slots of the additional defer duration T_(d)        are detected to be idle.    -   Step 6) (S1270) If the channel is sensed to be idle for all the        slot durations of the additional defer duration T_(d) (Y), step        4 proceeds. Otherwise (N), step 5 proceeds.

Table 8 shows that m_(p), a minimum contention window (CW), a maximumCW, a maximum channel occupancy time (MCOT), and an allowed CW size,which are applied to the CAP, vary depending on channel access priorityclasses.

TABLE 8 Channel Access Priority Class allowed (P) m_(p) CW_(min,p)CW_(max,p) T_(mcotp) CW_(p) sizes 1 1 3 7 2 ms {3, 7} 2 1 7 15 3 ms {7,15} 3 3 15 63 8 or 10 ms {15, 31, 63} 4 7 15 1023 8 or 10 ms {15, 31,63, 127, 255, 511, 1023}

The defer duration T_(d) is configured in the following order: durationT_(f) (16 us)+m_(p) consecutive sensing slot durations T_(sl) (9 us).T_(f) includes the sensing slot duration T_(sl) at the beginning of the16-us duration.

The following relationship is satisfied: C_(min,p)<=CW_(p)<=CW_(max,p).CW_(p) may be initially configured by CW_(p)=CW_(min,p) and updatedbefore step 1 based on HARQ-ACK feedback (e.g., ACK or NACK) for aprevious DL burst (e.g., PDSCH) (CW size update). For example, CW_(p)may be initialized to CW_(min,p) based on the HARQ-ACK feedback for theprevious DL burst. Alternatively, CW_(p) may be increased to the nexthighest allowed value or maintained as it is.

(2) Type 2 DL CAP Method

In the Type 2 DL CAP, the length of a time duration spanned by sensingslots sensed to be idle before transmission(s) may be determined. TheType 2 DL CAP is classified into Type 2A/2B/2C DL CAPs.

The Type 2A DL CAP may be applied to the following transmissions. In theType 2A DL CAP, the BS may perform transmission immediately after thechannel is sensed to be idle at least for a sensing durationT_(short_dl)=25 us. Here, T_(short_dl) includes the duration T_(f) (=16us) and one sensing slot duration immediately after the duration T_(f),where the duration T_(f) includes a sensing slot at the beginningthereof.

-   -   Transmission(s) initiated by the BS including (i) a discovery        burst only or (ii) a discovery burst multiplexed with        non-unicast information, or    -   Transmission(s) by the BS after a gap of 25 us from        transmission(s) by the UE within a shared channel occupancy.

The Type 2B DL CAP is applicable to transmission(s) performed by the BSafter a gap of 16 us from transmission(s) by the UE within a sharedchannel occupancy time. In the Type 2B DL CAP, the BS may performtransmission immediately after the channel is sensed to be idle forT_(f)=16 us. T_(f) includes a sensing slot within 9 us from the end ofthe duration. The Type 2C DL CAP is applicable to transmission(s)performed by the BS after a maximum of 16 us from transmission(s) by theUE within the shared channel occupancy time. In the Type 2C DL CAP, theBS does not perform channel sensing before performing transmission.

UL Signal Transmission Method in U-Band

The UE may perform a Type 1 or Type 2 CAP for UL signal transmission ina U-band. In general, the UE may perform the CAP (e.g., Type 1 or Type2) configured by the BS for UL signal transmission. For example, a ULgrant scheduling PUSCH transmission (e.g., DCI formats 0_0 and 0_1) mayinclude CAP type indication information for the UE.

(1) Type 1 UL CAP Method

In the Type 1 UL CAP, the length of a time duration spanned by sensingslots sensed to be idle before transmission(s) is random. The Type 1 ULCAP may be applied to the following transmissions.

-   -   PUSCH/SRS transmission(s) scheduled and/or configured by the BS    -   PUCCH transmission(s) scheduled and/or configured by the BS    -   Transmission(s) related to a Random Access Procedure (RAP)

FIG. 8 is a flowchart illustrating CAP operations performed by a UE totransmit a UL signal.

Referring to FIG. 8 , the UE may sense whether a channel is idle forsensing slot durations of a defer duration T_(d). Then, if a counter Nis zero, the UE may perform transmission (S1534). In this case, the UEmay adjust the counter N by sensing the channel for additional sensingslot duration(s) according to the following steps:

-   -   Step 1) (S1520) The UE sets N to N_(init) (N=N_(init)), where        N_(init) is a random number uniformly distributed between 0 and        CW_(p). Then, step 4 proceeds.    -   Step 2) (S1540) If N>0 and the UE determines to decrease the        counter, the UE sets N to N−1 (N=N−1).    -   Step 3) (S1550) The UE senses the channel for the additional        sensing slot duration. If the additional sensing slot duration        is idle (Y), step 4 proceeds. Otherwise (N), step 5 proceeds.    -   Step 4) (S1530) If N=0 (Y), the UE terminates the CAP (S1532).        Otherwise (N), step 2 proceeds.    -   Step 5) (S1560) The UE senses the channel until either a busy        sensing slot is detected within an additional defer duration        T_(d) or all the slots of the additional defer duration T_(d)        are detected to be idle.    -   Step 6) (S1570) If the channel is sensed to be idle for all the        slot durations of the additional defer duration T_(d) (Y), step        4 proceeds. Otherwise (N), step 5 proceeds.

Table 9 shows that m_(p), a minimum CW, a maximum CW, an MCOT, and anallowed CW size, which are applied to the CAP, vary depending on channelaccess priority classes.

TABLE 9 Channel Access Priority Class allowed (P) m_(p) CW_(min,p)CW_(max,p) T_(ulmcot,p) CW_(p) sizes 1 2 3 7 2 ms {3, 7} 2 2 7 15 4 ms{7, 15} 3 3 15 1023 6 ms or 10 ms {15, 31, 63, 127, 255, 511, 1023} 4 715 1023 6 ms or 10 ms {15, 31, 63, 127, 255, 511, 1023}

The defer duration T_(d) is configured in the following order: durationT_(f) (16 us)+m_(p) consecutive sensing slot durations T_(sl) (9 us).T_(f) includes the sensing slot duration T_(sl) at the beginning of the16-us duration.

The following relationship is satisfied: CW_(min,p)<=CW_(p)<=CW_(max,p).CW_(p) may be initially configured by CW_(p)=CW_(min,p) and updatedbefore step 1 based on an explicit/implicit reception response for aprevious UL burst (e.g., PUSCH) (CW size update). For example, CW_(p)may be initialized to CW_(min,p) based on the explicit/implicitreception response for the previous UL burst. Alternatively, CW_(p) maybe increased to the next highest allowed value or maintained as it is.

(2) Type 2 UL CAP Method

In the Type 2 UL CAP, the length of a time duration spanned by sensingslots sensed to be idle before transmission(s) may be determined. TheType 2 UL CAP is classified into Type 2A/2B/2C UL CAPs. In the Type 2AUL CAP, the UE may perform transmission immediately after the channel issensed to be idle at least for a sensing duration T_(short_dl)=25 us.Here, T_(short_dl) includes the duration T_(f) (=16 us) and one sensingslot duration immediately after the duration T_(f). In the Type 2A ULCAP, T_(f) includes a sensing slot at the beginning thereof. In the Type2B UL CAP, the UE may perform transmission immediately after the channelis sensed to be idle for the sensing duration T_(f)=16 us. In the Type2B UL CAP, T_(f) includes a sensing slot within 9 us from the end of theduration. In the Type 2C UL CAP, the UE does not perform channel sensingbefore performing transmission.

RB Interlace

FIG. 9 illustrates an RB interlace. In a shared spectrum, a set ofinconsecutive RBs (at the regular interval) (or a single RB) in thefrequency domain may be defined as a resource unit used/allocated totransmit a UL (physical) channel/signal in consideration of regulationson occupied channel bandwidth (OCB) and power spectral density (PSD).Such a set of inconsecutive RBs is defined as the RB interlace (orinterlace) for convenience.

Referring to FIG. 9 , a plurality of RB interlaces (interlaces) may bedefined in a frequency bandwidth. Here, the frequency bandwidth mayinclude a (wideband) cell/CC/BWP/RB set, and the RB may include a PRB.For example, interlace #m∈{0, 1, . . . , M−1} may consist of (common)RBs {m, M+m, 2M+m, 3M+m, . . . }, where M represents the number ofinterlaces. A transmitter (e.g., UE) may use one or more interlaces totransmit a signal/channel. The signal/channel may include a PUCCH orPUSCH.

2. Random Access Procedure

FIGS. 10A and 10B illustrate random access procedures. FIG. 10Aillustrates the contention-based random access procedure, and FIG. 10Billustrates the dedicated random access procedure.

Referring to FIG. 10A, the contention-based random access procedureincludes the following four steps. The messages transmitted in steps 1to 4 may be referred to as message 1 (Msg1) to message 4 (Msg4),respectively.

-   -   Step 1: The UE transmits an RACH preamble on a PRACH.    -   Step 2: The UE receives a random access response (RAR) on a        DL-SCH from the BS.    -   Step 3: The UE transmits a Layer 2 (L2)/Layer 3 (L3) message on        a UL-SCH to the BS.    -   Step 4: The UE receives a contention resolution message on the        DL-SCH from the BS.

The UE may receive random access information in system information fromthe BS.

When the UE needs random access, the UE transmits an RACH preamble tothe BS as in step 1. The BS may identify each RACH preamble by atime/frequency resource (RACH occasion (RO)) in which the RACH preambleis transmitted, and a preamble index (PI).

Upon receipt of the RACH preamble from the UE, the BS transmits an RARmessage to the UE as in step 2. To receive the RAR message, the UEmonitors an L1/L2 PDCCH with a cyclic redundancy check (CRC) masked witha random access-RNTI (RA-RNTI), including scheduling information for theRAR message, within a preconfigured time window (e.g.,ra-ResponseWindow). The PDCCH masked with the RA-RNTI may be transmittedonly in a common search space. When receiving a scheduling signal maskedwith the RA-RNTI, the UE may receive an RAR message on a PDSCH indicatedby the scheduling information. The UE then checks whether there is RARinformation directed to the UE in the RAR message. The presence orabsence of the RAR information directed to the UE may be determined bychecking whether there is a random access preamble ID (RAPID) for thepreamble transmitted by the UE. The index of the preamble transmitted bythe UE may be identical to the RAPID. The RAR information includes theindex of the corresponding RACH preamble, timing offset information(e.g., timing advance command (TAC)) for UL synchronization, ULscheduling information (e.g., UL grant) for Msg3 transmission, and UEtemporary identification information (e.g., temporary-C-RNTI (TC-RNTI)).

Upon receipt of the RAR information, the UE transmits UL-SCH data (Msg3)on a PUSCH according to the UL scheduling information and the timingoffset value, as in step 3. Msg3 may include the ID (or global ID) ofthe UE. Alternatively, Msg3 may include RRC connection request-relatedinformation (e.g., RRCSetupRequest message) for initial access. Inaddition, Msg3 may include a buffer status report (BSR) on the amount ofdata available for transmission at the UE.

After receiving the UL-SCH data, the BS transmits a contentionresolution message (Msg4) to the UE as in step 4. When the UE receivesthe contention resolution message and succeeds in contention resolution,the TC-RNTI is changed to a C-RNTI. Msg4 may include the ID of the UEand/or RRC connection-related information (e.g., an RRC Setup message).When information transmitted in Msg3 does not match information receivedin Msg4, or when the UE has not received Msg4 for a predetermined time,the UE may retransmit Msg3, determining that the contention resolutionhas failed.

Referring to FIG. 10B, the dedicated random access procedure includesthe following three steps. Messages transmitted in steps 0 to 2 may bereferred to as Msg0 to Msg2, respectively. The BS may trigger thededicated random access procedure by a PDCCH serving the purpose ofcommanding RACH preamble transmission (hereinafter, referred to as aPDCCH order).

-   -   Step 0: The BS allocates an RACH preamble to the UE by dedicated        signaling.    -   Step 1: The UE transmits the RACH preamble on a PRACH.    -   Step 2: The UE receives an RAR on a DL-SCH from the BS.

Steps 1 and 2 of the dedicated random access procedure may be the sameas steps 1 and 2 of the contention-based random access procedure.

In NR, DCI format 1_0 is used to initiate a non-contention-based randomaccess procedure by a PDCCH order. DCI format 1_0 is used to schedule aPDSCH in one DL cell. When the CRC of DCI format 1_0 is scrambled with aC-RNTI, and all bits of a “Frequency domain resource assignment” fieldare 1s, DCI format 1_0 is used as a PDCCH order indicating a randomaccess procedure. In this case, the fields of DCI format 1_0 areconfigured as follows.

-   -   RA preamble index: 6 bits    -   UL/supplementary UL (SUL) indicator: 1 bit. When the bits of the        RA preamble index are all non-zeroes and SUL is configured for        the UE in the cell, the UL/SUL indicator indicates a UL carrier        in which a PRACH is transmitted in the cell. Otherwise, it is        reserved.    -   SSB (Synchronization Signal/Physical Broadcast Channel) index: 6        bits. When the bits of the RA preamble index are all non-zeroes,        the SSB indicator indicates an SSB used to determine an RACH        occasion for PRACH transmission. Otherwise, it is reserved.    -   PRACH mask index: 4 bits. When the bits of the RA preamble index        are all non-zeroes, the PRACH mask index indicates an RACH        occasion associated with the SSB indicated by the SSB index.        Otherwise, it is reserved.    -   Reserved: 10 bits

When DCI format 1_0 does not correspond to a PDCCH order, DCI format 1_0includes fields used to schedule a PDSCH (e.g., a time domain resourceassignment, a modulation and coding scheme (MCS), an HARQ processnumber, a PDSCH-to-HARQ feedback timing indicator, and so on).

2-Step Random Access Procedure

In the prior art, random access is performed by a 4-step procedure asdescribed above. In the legacy LTE system, an average of 15.5 ms isrequired for the 4-step random access procedure.

TABLE 10 Component Description Time (ms) 1 Average delay due to RACHscheduling period (1 ms RACH cycle) 0.5 2 RACH Preamble 1 3-4 Preambledetection and transmission of RA response (Time 3 between the end RACHtransmission and UE’s reception of scheduling grant and timingadjustment) 5 UE Processing Delay (decoding of scheduling grant, timingalignment 5 and C-RNTI assignment + L1 encoding of RRC ConnectionRequest) 6 Transmission of RRC and NAS Request 1 7 Processing delay ineNB (L2 and RRC) 4 8 Transmisson of RRC Connection Set-up (and UL grant)1

The NR system may require lower latency than conventional systems. Whenrandom access occurs in a U-band, the random access may be terminated,that is, contention may be resolved only if the UE and BS sequentiallysucceed in LBT in all steps of the 4-step random access procedure. Ifthe LBT fails even in one step of the 4-step random access procedure,resource efficiency may decrease, and latency may increase. If the LBTfails in a scheduling/transmission process associated with Msg2 or Msg3,the resource efficiency may significantly decrease, and the latency maysignificantly increase. For random access in an L-band, low latency maybe required in various scenarios of the NR system. Therefore, a 2-steprandom access procedure may be performed in the L-band as well.

As illustrated in FIG. 10A, the 2-step random access procedure mayinclude two steps: transmission of a UL signal (referred to as MsgA)from the UE to the BS and transmission of a DL signal (referred to asMsgB) from the BS to the UE.

The following description focuses on the initial access procedure, butthe proposed methods may be equally applied to the random accessprocedure after the UE and BS establish an RRC connection. Further, arandom access preamble and a PUSCH part may be transmitted together in anon-contention random access procedure as shown in FIG. 10B.

While not shown, the BS may transmit a PDCCH for scheduling MsgB to theUE, which may be referred to as an MsgB PDCCH.

3. Random Access Procedure in U-Band

The above descriptions (NR frame structure, RACH, U-band system, etc.)are applicable in combination with methods proposed in the presentdisclosure, which will be described later. Alternatively, thedescriptions may clarify the technical features of the methods proposedin the present disclosure.

As described above, the Wi-Fi standard (802.11ac) specifies a CCAthreshold of −62 dBm for non-Wi-Fi signals and a CCA threshold of −82dBm for Wi-Fi signals. In other words, a station (STA) or access point(AP) of the Wi-Fi system may transmit no signal in a specific band ifthe STA or AP receives a signal from a device not included in the Wi-Fisystem in the specific band at a power of −62 dBm or higher.

The physical random access channel (PRACH) format may include a longRACH format and a short RACH format. A PRACH corresponding to the longRACH format is composed of a length 839 sequence. A PRACH correspondingto the short RACH format is composed of a 139-length sequence.Hereinafter, a structure of a sequence configured by the short RACHformat is proposed. In the frequency range 1 (FR1) band of less than 6GHz, the SCS of the short RACH format corresponds to 15 and/or 30 kHz.The PRACH corresponding to the short RACH format may be transmitted over12 RBs as shown in FIGS. 10A and 10B. 12 RBs include 144 REs, and thePRACH may be transmitted on 139 tones (139 REs) among 144 REs. FIG. 12shows that two REs having the lowest indexes and three REs having thehighest indexes among the 144 REs correspond to null tones. However, thepositions of the null tones may be different from those shown in FIG. 12.

In the present disclosure, the short RACH format may be referred to as ashort PRACH format, and the long RACH format may be referred to as along PRACH format. The PRACH format may be referred to as a preambleformat.

The short PRACH format may be composed of values defined in Table 11.

TABLE 11 Format L_(RA) Δf^(RA) N_(u) N_(CP) ^(RA) A1 139 15 × 2^(μ) kHz 2 × 2048κ × 2^(−μ)  288κ × 2^(−μ) A2 139 15 × 2^(μ) kHz  4 × 2048κ ×2^(−μ)  576κ × 2^(−μ) A3 139 15 × 2^(μ) kHz  6 × 2048κ × 2^(−μ)  864κ ×2^(−μ) B1 139 15 × 2^(μ) kHz  2 × 2048κ × 2^(−μ)  216κ × 2^(−μ) B2 13915 × 2^(μ) kHz  4 × 2048κ × 2^(−μ)  360κ × 2^(−μ) B3 139 15 × 2^(μ) kHz 6 × 2048κ × 2^(−μ)  504κ × 2^(−μ) B4 139 15 × 2^(μ) kHz 12 × 2048κ ×2^(−μ)  936κ × 2^(−μ) C0 139 15 × 2^(μ) kHz 2048κ × 2^(−μ) 1240κ ×2^(−μ) C1 139 15 × 2^(μ) kHz  4 × 2048κ × 2^(−μ) 2048κ × 2^(−μ)

In Table 11, L_(RA) is the length of the RACH sequence, Δf_(RA) is theSCS applied to the RACH, and κ=T_(s)/T_(c)=64. For μ∈{0,1,2,3}, μ isdefined as one of 0, 1, 2, and 3 according to the SCS. For example, μ isdefined as 0 for the 15 kHz SCS, and defined as 1 for the 30 kHz SCS.

A BS may announce, through higher layer signaling, which PRACH formatcan be transmitted at a specific timing for a specific duration, and howmany ROs are in the corresponding slot. Table 6.3.3.2-2 to Table6.3.3.2-4 of the standard 38.211 correspond to this case. Table 12 showsonly a few specific excerpts from the indexes that may use A1, A2, A3,B1, B2, or B3 or a combination thereof in Table 6.3.3.2-3 of thestandard 38.211.

TABLE 12 N_(t) ^(RA,slot), number of time- Number domain of PRACH PRACHoccasions PRACH slots within a N_(dur) ^(RA), Configuration Preamblen_(SFN) mod x = y Starting within a PRACH PRACH Index format x ySubframe number symbol subframe slot duration 81 A1 1 0 4, 9 0 1 6 2 82A1 1 0 7, 9 7 1 3 2 100 A2 1 0 9 9 1 1 4 101 A2 1 0 9 0 1 3 4 127 A3 1 04, 9 0 1 2 6 128 A3 1 0 7, 9 7 1 1 6 142 B1 1 0 4, 9 2 1 6 2 143 B1 1 07, 9 8 1 3 2 221 A1/B1 1 0 4, 9 2 1 6 2 222 A1/B1 1 0 7, 9 8 1 3 2 235A2/B2 1 0 4, 9 0 1 3 4 236 A2/B2 1 0 7, 9 6 1 2 4 251 A3/B3 1 0 4, 9 0 12 6 252 A3/B3 1 0 7, 9 2 1 2 6

It may be seen from Table 12 how many ROs are defined in the RACH slotfor each preamble format (see Number of time domain PRACH occasionswithin a PRACH slot in Table 12), how many Orthogonal frequency-divisionmultiplexing (OFDM) symbols are occupied by the PRACH preamble of eachpreamble format (see PRACH duration in Table 12). In addition, thestarting symbol of the first RO may be indicated for each preambleformat, and accordingly information on a point in time at which the ROstarts in the RACH slot may be transmitted/received between the BS andthe UE. FIG. 13 shows how ROs are configured in a RACH slot for eachPRACH configuration index value of Table 12.

A device operating in the unlicensed band checks whether a channel onwhich a signal is to be transmitted is in an idle mode or a busy mode.When a channel is in the idle mode, the signal is transmitted on thechannel. When the channel is in the busy mode, the device to transmitthe signal waits until the channel turns into the idle mode beforetransmitting the signal. As previously described with reference to FIGS.6 and 7 , such an operation may be referred to as an LBT or channelaccess scheme. In addition, there may be LBT categories as shown inTable 13.

TABLE 13 The channel access schemes for NR-based access for unlicensedspectrum can be classified into the following categories: Category 1:Immediate transmission after a short switching gap This is used for atransmitter to immediately transmit after a switching gap inside a COT.The switching gap from reception to transmission is to accommodate thetransceiver turnaround time and is no longer than 16 μs. Category 2: LBTwithout random back-off The duration of time that the channel is sensedto be idle before the transmitting entity transmits is deterministic.Category 3: LBT with random back-off with a contention window of fixedsize The LBT procedure has the following procedure as one of itscomponents. The transmitting entity draws a random number N within acontention window. The use of the contention window is specified by theminimum and maximum value of N. The use of the contention window isfixed. The random number N is used in the LBT procedure to determine theduration of time that the channel is sensed to be idle before thetransmitting entity transmits on the channel. Category 4: LBT withrandom back-off with a contention window of variable size The LBTprocedure has the following as one of its components. The transmittingentity draws a random number N within a contention window. The size ofcontention window is specified by the minimum and maximum value of N.The transmitting entity can vary the size of the contention window whendrawing the random number N. The random number N is used in the LBTprocedure to detemine the duration of time that the channel is sensed tobe idle before the transmitting entity transmits on the channel.

LBT corresponding to Category 1 is a method of channel access withoutLBT. According to the LBT corresponding to Category 1, when the time gapfrom the time at which a specific node occupies the channel to a timeimmediately before the next transmission is shorter than 16 us, thespecific node may access the channel regardless of the mode. Next,Category 2 LBT is a method of access to a channel after performingone-shot LBT without a back-off counter value. According to the LBTcorresponding to Category 2, a specific node performs transmission afterdetermining whether the channel is idle for 16 us (or 25 us).

For LBTs corresponding to Category 3 and Category 4, a backoff countervalue is randomly selected within a contention window (CW). In thepresent disclosure, the LBT corresponding to Category 3 may be referredto as Cat 3 LBT, and the LBT corresponding to Category 4 may be referredto as Cat 4 LBT. For the LBT corresponding to Category 3, a backoffcounter value is randomly selected based on a fixed contention windowsize value at all times. For the LBT corresponding to Category 4, thecontention window size starts from the initial minimum contention windowsize value and is incremented by 1 step in the allowed candidates eachtime the LBT fails. The maximum and minimum values of the contentionwindow size and the allowed candidate contention window size values arepredefined for each channel access priority class (see Tables 3 and 4).For example, in the case of Cat 4 LBT whose channel access priorityclass is 4, the UE initially selects a backoff counter value randomlyfrom among 0 to 15. When the UE fails in LBT, it randomly selects abackoff counter value from among 0 to 31.

When the channel is idle for 16+9×mp+K×9 us, the UE selecting thebackoff counter value based on the values defined in Table 9 performsuplink transmission indicated and/or configured by the BS. K is theselected backoff counter value, and m_(p) corresponds to a slot timeapplied according to the channel access priority class. The channelaccess priority class and LBT category for PRACH transmission may beconfigured as shown in Table 14.

TABLE 14 Cat 2 LBT Cat 4 LBT PUSCH (including at N/A except for theChannel access priority class is least UL-SCH with cases discussed inselected according to the data user plane data) Note 2 below SRS-onlyN/A Cat4 with lowest channel access priority class value (as in LTEeLAA) RACH-only (see Note 2) Cat4 with lowest channel access priorityclass value PUCCH-only (see Note 2) Cat4 with lowest channel accesspriority class value Note 2: Applicability of a channel access schemeother than Cat 4 for the following signals/channels have been discussedand details are to be determined when the specifications are developed:UL control information including UCI only on PUSCH, e.g. HARQ-ACK,Scheduling Request, and Channel State Information Random Access

Based on the values derivable from Tables 13 and 14, the UE may startPRACH transmission when the channel is idle for 16+9*2+K*9 (=34+K*9) us.As described above, the backoff counter value K is randomly selectedwithin the size-varying contention window size.

The 2-step random access procedure described above includes transmissionof message A (including Msg. A, PRACH preamble and Msg3 PUSCH) from theUE and transmission of message B (including Msg. B, RAR and Msg. 4PDSCH) from the BS. For simplicity, in the present disclosure, a timeand frequency resource at which the PRACH preamble signal of Msg. A ismapped/transmitted is defined as a RACH occasion (RO), and a time andfrequency resource at which the Msg. 3 PUSCH signal ismapped/transmitted is defined as a PUSCH occasion (PO). In the followingdescription, a specific method of configuring Msg. A is proposed. TheRACH preamble constituting Msg. A may be referred to as a Msg. A RACHpreamble and Msg. A PRACH. The Msg. 3 PUSCH constituting Msg. A may bereferred to as a Msg. A PUSCH. The RAR constituting Msg. B may bereferred to as a Msg. B RAR. The Msg. 4 PDSCH constituting Msg. B may bereferred to as a Msg. B PDSCH.

Hereinafter, an operation of a UE for performing UL transmission using aUL interlace, proposed in the present disclosure, will be described.

(1) First, the UE receives UL interlace configuration information for ULtransmission from the BS. The UL interlace configuration information mayinclude information about a UL interlace index for a UL interlace thatsatisfies the defined OCB requirements for each SCS. (2) The UEdetermines at least one UL interlace based on the UL interlaceconfiguration information. (3) The UE performs UL transmission to the BSon the determined at least one UL interlace.

For more details, reference will be made to methods described below.That is, the methods described below may be combined with the procedureof operations (1) to (3) described above to achieve the objects/effectsproposed in the present disclosure. In addition, the methods describedbelow may be combined with the procedure described in 2. Random AccessProcedure to achieve the objects/effects proposed in the presentdisclosure. In the present disclosure, the term “unlicensed band” may bereplaced and interchangeably used with the terms “shared spectrum.”

3.1 Embodiment 1: Frequency Domain Gap for Msg. A PUSCH Transmission

As described above, the UE transmits Msg. A PUSCH through apredetermined PO after transmitting the RACH preamble included in Msg.A. It is assumed that the BS has configured multiple POs operativelyconnected to one RO (or multiple ROs) as consecutive interlace indexespresent in the same slot. When there are multiple UEs which are totransmit Msg. A PUSCH in a PO, timing advance (TA) values configured forthe multiple UEs may be different from each other. There is no frequencygap between consecutive interlace indexes, as defined in theconventional system. Accordingly, when the TA values of the Msg. APUSCHs transmitted by multiple UEs are different from each other, theMsg. A PUSCH reception performance of the BS may be degraded. InEmbodiment 1, methods to prevent degradation of reception performancefor Msg. A PUSCH are proposed.

Proposed Method 1-1: Providing a PRB level frequency gap betweenconsecutive interlace indexes

Opt 1-1-1) Allocating a specific interlace index for Msg. A PUSCHtransmission, and excluding other specific interlace indexes from Msg. APUSCH transmission

As an example, when a 30 kHz SCS is used, a total of 5 interlace indexesmay be present in a 20 MHz bandwidth. When the interlace indexes are #0,#1, #2, #3, and #4, the BS may define indexes #0, #2, and #4 as a PO forMsg. A PUSCH transmission, and exclude indexes #1 and #3 from Msg. APUSCH transmission.

Opt 1-1-2) Indicating a starting PRB offset together with a specificinterlace index (wherein the starting PRB offset may be set smaller thanthe interlace PRB gap).

As an example, when 30 kHz SCS is used, a total of 5 interlace indexesmay be present in a 20 MHz bandwidth. When the interlace indexes are #0,#1, #2, #3, and #4, the BS sets the interlace index #0 to a PO for Msg.A PUSCH transmission and sets the starting PRB offset to 0. In addition,the BS may set the interlace index #1 to PO for Msg. A PUSCHtransmission, and set the starting PRB offset to 1 RB. In addition, theBS may set the interlace index #2 to a PO for Msg. A PUSCH transmission,and set the starting PRB offset to 2 RBs.

When the starting PRB offset is set as described above, a result ofcalculating the starting PRB offset in combination with the interlaceindex may cause Msg. A PUSCH to be transmitted in a frequency bandoutside the LBT subband. The UE does not transmit Msg. A PUSCH in a PRBin a frequency band outside the LBT subband. For example, Msg. A PUSCHmay be dropped in the PRB in a frequency band outside the LBT subband.The BS may also expect that the UE does not transmit Msg. A PUSCH in thePRB in the frequency band outside the LBT subband.

As a specific example, when an offset of Y PRBs is indicated to theinterlace index #X composed of 11 RBs, and the (highest index) last 1PRB is out of the LBT subband, the UE may configure the interlace onlywith 10 RBs excluding the last 1 PRB to transmit the PUSCH.

Opt 1-1-3) Msg. A PUSCH resource sets composed of specific interlaceindexes may be defined and the BS may indicate one of the defined sets.

As an example, when 30 kHz SCS is used, a total of 5 interlace indexesmay be present in a 20 MHz bandwidth. When the interlace indexes are #0,#1, #2, #3, and #4, Msg. A PUSCH resource sets may be defined as shownin Table 15.

TABLE 15 Index Interlace index candidates for Msg. A PUSCH resource set0 All interlace index (e.g., #0, #1, #2, #3, #4) 1 Even numberedinterlace index (e.g., #0, #2, #4) 2 Odd numbered interlace index (e.g.,#1, #3) 3 Reserved

The BS may select and indicate one of the indexes defined in Table 15for Msg. A PUSCH transmission. For example, when the BS indicates index1, even numbered interlace indexes may be set to PO, and thus a 1 PRBgap may be generated between interlace resources.

According to Opt 1-1-3, an RB level (e.g., 1RB) gap is guaranteedbetween interlaces on which Msg. A PUSCH is actually transmitted, andtherefore degradation of reception performance caused by different TAsmay not occur at the BS side. However, when available interlace indexesare fewer than a specific level (e.g., 5 interlaces in 30 kHz SCS),providing an RB level gap may result in lack of interlace indexesavailable as a PO, thereby increasing resource overhead.

Additionally, according to Opt 1-1-3, DMRS may also be transmittedaccording to the frequency resource of the PO on which the Msg. A PUSCHis transmitted.

Proposed Method 1-2: An RE level frequency gap may be provided betweenconsecutive interlace indexes.

Opt 1-2-1) Among the REs in the PRB constituting an interlacecorresponding to a specific index, N (N<12) REs may be excluded from thePO for Msg. A PUSCH transmission.

As an example, for a PRB constituting the interlace corresponding to aspecific index, Msg. A PUSCH may be transmitted in the REs excluding one(lowest or highest) RE (i.e., by rate matching or dropping or puncturingthe same). However, since each PRB is composed of 11 REs, it may not besuitable for the DFT size. The DFT size may be set to a multiple of 2,3, or 5.

As another example, in the PRB constituting the interlace correspondingto a specific index, Msg. A PUSCH may be transmitted in the REsexcluding two (lowest and highest, or 2 lowest, or 2 highest) REs (i.e.,by rate matching or dropping or puncturing the same). Since each PRB iscomposed of 10 REs, the DFT size is configured appropriately.

As another example, the BS may configure information related to the RElevel gap (e.g., the number and/or positions of REs in 1 PRB necessary(or unnecessary) for Msg. A PUSCH transmission). The RE level gap may beconfigured differently according to the SCS value for Msg. A.

According to Opt 1-2-1, in an RE at the same position as the RE in whichthe Msg. A PUSCH is configured not to be transmitted, the DMRS may beconfigured not to be transmitted (e.g., the DMRS may be punctured ordropped).

Alternatively, Msg. in an RE at the same position as the RE in whichMsg. A PUSCH is configured not to be transmitted, a DMRS resourceavailable for transmission may be configured to be excluded from the PO.

For example, Msg. A PUSCH may be configured to be transmitted withoutusing the highest 1 RE (e.g., by puncturing or dropping the same). Inthe case of DMRS configuration type 1 in FIG. 14 , DMRS resourcesindicated by hatched portions (corresponding to the highest 1 RE) may beexcluded from the PO (i.e., when the RE positioned at the top is RE #11,DMRS resources composed of REs #11, #9, #7, #5, #3, and #1 may beexcluded). In addition, in the case of DMRS configuration type 2 in FIG.14 , DMRS resources indicated by a cross pattern (corresponding to thehighest 1 RE) may be excluded from the PO (i.e., when the RE positionedat the top is RE #11, DMRS resources composed of REs corresponding to#11, #10, #5, and #4 may be excluded).

Opt 1-2-2) A starting RE offset may be indicated together with aspecific interlace index (wherein the RE offset may be set to be smallerthan 1 PRB (or a PRB gap in the interlace)).

As an example, when 30 kHz SCS is used, a total of 5 interlace indexesmay be present in a 20 MHz bandwidth. When the interlace indexes are #0,#1, #2, #3, and #4, the BS sets the interlace index #0 to a PO for Msg.A PUSCH transmission and sets the starting RE offset to 0. In addition,the BS may set the interlace index #1 to a PO for Msg. A PUSCHtransmission, and set the starting RE offset to 1 RE. In addition, theBS may set the interlace index #2 to a PO for Msg. A PUSCH transmission,and indicate the starting RE offset as 2 REs. The starting RE offset maytake the form of {interlace index X RE offset}.

When the starting RE offset is set as described above, a result ofcalculating the starting RE offset in combination with the interlaceindex may cause Msg. A PUSCH to be transmitted in a frequency bandoutside the LBT subband. The UE does not transmit Msg. A PUSCH in a PRBin a frequency band outside the LBT subband. For example, Msg. A PUSCHmay be dropped in the PRB in a frequency band outside the LBT subband.The BS may also expect that the UE does not transmit Msg. A PUSCH in thePRB in the frequency band outside the LBT subband.

As a specific example, when an offset of Y REs is indicated to theinterlace index #X composed of 11 RBs, and some REs in the (highestindex) last 1 PRB are out of the LBT subband, the UE may configure theinterlace only with 10 RBs excluding the last 1 PRB to transmit thePUSCH.

Additionally, according to Opt 1-2-2, Msg. DMRS may also be transmittedaccording to the frequency resource of the PO on which the Msg. A PUSCHis transmitted.

According to Opt 1-2-2, an RE level (e.g., 1RE) gap is guaranteedbetween interlaces on which Msg. A PUSCH is actually transmitted, andtherefore degradation of reception performance caused by different TAsmay not occur at the BS side.

Proposed Method 1-3: A new interlace structure with frequency spacingmay be introduced.

A new interlace structure is proposed such that a gap of k REs is alwayspresent between consecutive interlace indexes (e.g., k=1).

The new interlace structure in which the gap of k REs is present may beconfigured to be used only for Msg. A PUSCH transmission in the 2-steprandom access procedure.

The existing Msg. 3 PUSCH and other channels (e.g., unicast PUSCH,PUCCH, etc.) are configured to use the interlace structure (with no REgap) defined in the conventional system.

For example, the number of PRBs constituting the actual initial ULbandwidth part (BWP) is 48 (based on 30 kHz SCS). However, for theinterlace structure in which the 1 RE gap is present, 44 PRBs mayconstitute 5 interlaces and 1 RE gaps are configured between consecutiveinterlace indexes.

In addition, to satisfy OCB requirements, a mid-gap corresponding to 5REs may be added. 48 PRB*12 RE=576 RE, and 44 PRB*13 RE=572 RE.Therefore, 5 REs (the remaining 4 REs and 1 RE present after the lastPRB) may be placed before the 23rd PRB and used as the mid-gap.

Alt 1-3-1) It is assumed that there are a total of 5 interlacesincluding 4 interlaces composed of 9 PRBs and one interlace composed of8 PRBs (see FIG. 15 ).

The four interlaces composed of 9 PRBs satisfy the OCB requirements asfollows: {30 (kHz)*5(PRB interval in interlace)*13(12 RE+1 RE gap)*8(PRB)}+{30 (kHz)*12 (RE)*1(PRB)}+{30 (kHz)*5 (mid-gap RE)}=16110 (kHz).

Four interlaces composed of 8 PRBs fail to satisfy the OCB requirements:{30 (kHz)*5(PRB gap in interlace)*13(12 RE+1 RE gap)*7 (PRB)}+{30(kHz)*12 (RE)*1 (PRB)}+{30 (kHz)*5 (mid-gap RE)}=14160 (kHz)

Alt 1-3-2) 4 interlaces composed of 11 PRBs may be present (see FIG. 16).

The 4 interlaces composed of 11 PRBs satisfy the OCB requirements asfollows: {30 (kHz)*4 (PRB gap in interlace)*13(12 RE+1 RE gap)*10(PRB)}+{30 (kHz)*12 (RE)*1 (PRB)}+{30 (kHz)*5 (mid-gap RE)}=16110 (kHz).

When a new interlace structure with a gap of k REs is introduced byProposed Method 1-3, an RE level (e.g., 1RE) gap is guaranteed betweeninterlaces in which Msg. A PUSCH is actually transmitted. Therefore,reception performance degradation caused by different TAs may not occurat the BS side. In addition, since additional signaling from the BS isnot required, signaling overhead may also be reduced.

According to Proposed Method 1-3, DMRS may also be transmitted accordingto the frequency resource of the PO through which the Msg. A PUSCH istransmitted.

Proposed Method 1-4: The UE may transmit Msg. A PUSCH by puncturing orrate matching a specific interlace index belonging to the PO resourceindicated by the BS.

In the case where the BS configures interlace indexes for each of thePOs, and the adjacent POs are consecutively configured without afrequency gap therebetween, when a guard band (having, for example, 1-RBsize) is configured between adjacent POs, the actual Msg. A PUSCH may betransmitted in interlaces corresponding to the remaining interlaceindexes except for a specific (e.g., one) interlace index within theconfigured PO. When no (non-zero) guard band is configured betweenadjacent POs, the actual Msg. A PUSCH may be transmitted in interlacescorresponding to all interlace indexes in the PO configured by the BS.

As an example, when the BS allocates N (e.g., N=2) (or more) interlaceindexes for each PO, the actual Msg. A PUSCH may be transmitted usingthe interlaces except for the highest (or lowest) interlace index amongthe N interlaces. All PRBs constituting the highest (or lowest)interlace index may be punctured or rate matched in Msg. A PUSCHtransmission.

As another example, when the BS allocates N (e.g., N=2) (or more)interlace indexes for each PO, the actual Msg. A PUSCH may betransmitted using the interlaces except for the interlace in which thefirst or last PRB is at the highest (or lowest) frequency. All PRBsconstituting the interlace index in which the starting or last PRB ispositioned at the highest (or lowest) frequency may be punctured or ratematched in Msg. A PUSCH transmission.

As another example, when the BS allocates N (e.g., N=2) (or more)interlace indexes for each PO, the actual Msg. A PUSCH may betransmitted using the interlaces except for the interlace configured asthe last (e.g., highest) resource index (or the first (e.g., lowest)resource index) in the RRC configuration (for PO resourceconfiguration). All PRBs constituting the interlace configured as thelast (i.e., highest) (or first (i.e., lowest)) resource index in the RRCconfiguration may be punctured or rate matched in Msg. A PUSCHtransmission.

Proposed Method 1-5: The UE may transmit Msg. A PUSCH with an interlacegap placed between multiple PO resources indicated by the BS.

In the case where the BS configures POs adjacent to each other, when aguard band (having, for example, 1-RB size) is configured betweenadjacent POs, a PO to be used for actual Msg. A PUSCH transmission maybe reconfigured by inserting X (e.g. X=1) interlaces (or a set ofnon-consecutive or equally spaced PRBs corresponding thereto) betweenadjacent POs as a gap. When no (non-zero) guard band is configured, theactual Msg. A PUSCH may be transmitted using the interlace in theoriginally configured PO.

As an example, when the BS configures N POs adjacent to each other, a POto be used for the actual Msg. A PUSCH transmission may be configuredwith an interlace gap (corresponding to, for example, one interlace)placed between adjacent POs. Specifically, the interlace index set tothe PO at the lowest frequency position by the BS may be allocated tothe PO, and the PO at the second lowest position is assigned aninterlace index one interlace gap away from the lowest PO. In otherwords, an interlace index obtained by applying an offset correspondingto one interlace gap to the interlace index set for the PO by the BS isallocated. For example, for the PO at the second lowest position, “+1”may be applied to the interlace index allocated by the BS. For the K-thPO, an offset corresponding to K−1 interlace indexes may be applied tothe interlace index set for the PO by the BS. For example, for the K-thPO, “+K−1” may be applied to the interlace index set to the PO by theBS.

Assuming that there is one interlace gap between N POs, a frequency bandcorresponding to a total of N+N−1 interlaces is required to actuallyconfigure the N POs.

In the case where a specific PO is allocated to an unavailable frequencyband or invades other UL resources, the PO may be set to be invalid.

3.2 Embodiment 2: RO and PO in Same (or Consecutive) Slot Case

When an RO and a PO for the 2-step RACH are consecutively scheduled, theUE may share channel occupancy (CO) by performing the LBT procedure onlyonce. Accordingly, in Embodiment 2, methods for consecutively schedulingthe RO and the PO may be proposed.

Proposed Method 2-1: The BS may configure the last X OFDM symbol in slotN (i.e., OFDM symbols #14-X, . . . , #12, and #13 in slot N) as an RO,and configure the first Y OFDM symbols in slot N+1 (i.e., OFDM symbols#0, #1, . . . , and #Y−1 in slot N+1) as a PO (Assume that the RO and POare linked to each other).

After transmitting the Msg. A preamble on the configured RO, the UE mayoperate in Cat-1 LBT (no LBT) by sharing the CO because the gap betweenthe RO and the PO is 0, and then transmit the Msg. A PUSCH on the PO.

Proposed Method 2-1-1: In addition to Proposed Method 2-1, the BS mayconfigure the remaining OFDM symbols of slot N as an RO for 4-step RACH.In this case, an LBT gap may be required between ROs.

Specifically, when n ROs are configured in slot N, only the last RO maybe used as an RO for 2-step RACH, and the remaining ROs may be used asROs for 4-step RACH. Because the last RO is in contact with the PO inthe next slot N+1, it may be used for 2-step RACH. On the other hand,the remaining ROs may be used as ROs for 4-step RACH because they arenot in contact with the PO.

Proposed Method 2-2: When an RO and a PO (of the same Msg. A) areconfigured in the RACH slot without a gap therebetween, the last RO inslot N and the first PO in slot N+1 may be connected without a gap

The last RO may be shifted to the boundary of the slot N, or the endposition thereof may be extended to the boundary of slot N with thestarting position of the last RO fixed.

The connection between the last RO and the first PO may be establishedonly when the gap between the last RO and the first PO is less than orequal to a specific level. When the gap is greater than or equal to aspecific value, Msg. A may be configured while the last RO and the firstPO are not connected and the gap therebetween is maintained.

Proposed Method 2-3: The BS may configure multiple ROs and POsconsecutively present in a specific slot (without an gap between the ROsand the POs)

After transmitting the Msg. A preamble on an RO, the UE may operate inCat-1 LBT (no LBT) by sharing the CO because the gap between the RO andthe PO is 0, and then transmit the Msg. A PUSCH on the PO.

Specifically, in order to configure a structure as in Proposed Method2-3, ROs and POs may be consecutively configured, respectively, and theninformation indicating a valid (or invalid) occasion for each of the ROsand POs may be additionally transmitted.

For example, 6 ROs each composed of 2 OFDM symbols may be configured inslot N (assuming that a starting offset of 2 symbols is indicated andthe ROs are positioned from the third OFDM symbol), and 6 POs eachcomposed of 2 OFDM symbols may be configured in slot N (similarlyassuming that a starting offset by 2 symbols is indicated and the POsare positioned from the third OFDM symbol). Thereafter, the BS maytransmit information indicating that only even numbered ROs are validand odd numbered ROs are invalid, and information indicating that onlyodd numbered POs are valid and even numbered POs are invalid. Theinformation may be transmitted using a method such as a bit map or 1-biteven/odd selection. In slot N, three occasions of RO and PO may appearfrom the third OFDM symbol without an gap. Even in this case, an LBT gapmay be needed between the three occasions of RO and PO.

Proposed Method 2-4: Immediately after the LBT is successful (or at aspecific position that is present after the time when the LBT issuccessful), the UE may transmit an Msg. A preamble and thensubsequently transmit Msg. A PUSCH immediately.

For example, the BS configures the RO and PO in units of a plurality of(half) slots. After performing the LBT procedure within the configured(half) slots, the UE may transmit a preamble on the RO by applying aformat and repetition corresponding to a PRACH configuration index setimmediately after the time when the LBT is successful or set accordingto the symbol boundary (or (half) slot boundary) that is presentimmediately after the time when the LBT is successful. Subsequently, itmay transmit the Msg. A PUSCH on the PO.

In another example, the BS may configure ROs in the time domain so as tooverlap each other, and transmit the Msg. A preamble starting on thenearest RO from the LBT start time. Immediately thereafter, it maytransmit Msg. A PUSCH.

For example, the BS may configure 6-symbol ROs including RO #1, whichstarts from symbol #0, RO #2, which starts from symbol #1, RO #3, whichstarts from symbol #2, and so on. When the UE succeeds in Cat-4 LBTimmediately ahead of RO #3, it may transmit the Msg. A preamble on RO #3and transmit Msg. A PUSCH immediately thereafter.

According to Proposed Method 2-4, transmission occasions for the Msg. Apreamble and PUSCH may increase from the perspective of the UE, but thenumber of BDs may increase, which is a burden on the BS.

Specifically, when the band of the RO constituting the same Msg. A isset to be smaller than or different from the band of the PO, the RO andthe PO may be configured (in different slots) with a time gap placedtherebetween. Alternatively, when the band of the RO is smaller than ordifferent from the band of the PO and there is no time gap between theRO and the PO, only a portion aligned with the band of the RO may bedetermined as the PO resource. When the band of the RO is set to begreater than or equal to the band of the PO, the RO and the PO may beconfigured either with a time gap or without a time gap therebetween.

3.3 Embodiment 3: Resource Allocation Type for Msg. 3 PUSCH (or Msg. APUSCH)

When Msg. 3 PUSCH (or Msg. A PUSCH) is transmitted in the RACHprocedure, the UE needs to know whether the method of PRB level resourceallocation is used or the method of interlace level resource allocationis used.

As the most basic method, a default RA type for Msg. 3 PUSCH (or Msg. APUSCH) may be determined. In addition, the BS may configure an RA typethrough higher layer signaling (e.g., SIB or RMSI, etc.), therebyindicating the RA type (other than the default RA type) directly to theUE. That is, when there is no RA type for Msg. 3 PUSCH (or Msg. A PUSCH)directly configured by the BS, the BS and the UE may transmit andreceive Msg. 3 PUSCH (or Msg. A PUSCH) based on the default RA type.

Alternatively, the RA type for Msg. 3 PUSCH (or Msg. A PUSCH) may bedirectly indicated through Msg. 2 RAR (or Msg. B RAR). To this end, adefault RA type for Msg. 3 PUSCH (or Msg. A PUSCH) may be determined.When there is no RA type directly configured through the Msg. 2 RAR (orMsg. B RAR), the BS and the UE may transmit and receive Msg. 3 PUSCH (orMsg. A PUSCH) based on the default RA type.

3.4 Embodiment 4: CP Extension for Msg. A PRACH and Msg. A PUSCH

In the case where a RACH slot in which the Msg. A preamble istransmitted and a PUSCH slot in which the Msg. A PUSCH is transmittedare consecutively configured, an RO is positioned after the RACH slot,and a PO is positioned before the PUSCH slot, while the RO and the POare associated with each other (by the same Msg. A configuration), theUE may extend the CP of Msg. A PUSCH and use the RO and the PO throughonly one LBT procedure without a gap therebetween. In other words, theUE may perform the operation of channel occupancy (CO) sharing byextending the CP of Msg. A PUSCH to eliminate the gap between the RO andthe PO.

In this case, the size of a gap between the RO and the PO in which CPextension may be allowed and a situation and conditions in which CPextension of Msg. A PUSCH is allowed may be defined.

4-1) Size of the gap between the RO (or PRACH signal) and the PO (orPUSCH signal) in which CP extension is allowed

CP extension may be an operation of extending the PRACH signal to thePUSCH starting symbol to fill the gap between the RO and the PO with thePRACH signal, or extending the CP of the PUSCH starting symbol to thelast symbol of the PRACH to fill the gap between the RO and the PO withthe CP.

Alt 4-1-1) A gap size set to be smaller than or equal to 1-symbol (or1-symbol for 15 kHz SCS, 2-symbols for 30 kHz SCS, or 4-symbols for 60kHz SCS), the maximum gap in which CP extension defined in NR-U isallowed.

Alt 4-1-2) A gap size set to be smaller than or equal to 2-symbols (for15/30 kHz SCS) or 4-symbols (for 60 kHz SCS), which is the minimum gapdefined between the RO (or PRACH signal) and the PO (or PUSCH signal)for NR 2-step RACH)

Alt 4-1-3) The BS may indicate, through SIB, the maximum size of the gapin which CP extension is allowed.

4-2) Conditions for allowing CP extension between the RO (or PRACHsignal) and the PO (or PUSCH signal)

Alt 4-2-1) When the gap between the RO (PRACH) and the PO (PUSCH)associated therewith (by the same Msg. A configuration) satisfies thegap size of 4-1) above, CP extension may be allowed. Alternatively, theBS may indicate/set, through the SIB, whether the CP extension isallowed.

Alt 4-2-2) When the gap between the RO (PRACH) and the PO (PUSCH)associated therewith (by the same Msg. A configuration) satisfies thegap size of 4-1) above, while the PO is not associated with other ROsconfigured on a symbol different from that of the associated RO, thatis, when one PO is associated with an RO that satisfies the gap size andis also associated with an RO that does not satisfy the gap size, the CPextension may not be allowed. As an example, UE1 that has selected an ROthat does not satisfy the gap size may intend to transmit Msg. A PUSCHon a PO associated with the selected RO, and UE2 that has selected an ROthat satisfies the gap size may also intend to transmit Msg. A PUSCH onthe with the selected RO. In this case, the POs associated with the twoROs may be the same. UE1 may perform LBT once more before the PO, butUE2 may perform CP extension. Accordingly, UE1 may always fail in theLBT and fail to transmit the Msg. A PUSCH on the PO. Therefore, when onePO is associated with both an RO that satisfies the gap size and an ROthat does not satisfy the gap size, CP extension may not be allowed.Alternatively, the BS may indicate/set, through the SIB, whether the CPextension is allowed.

Alt 4-2-3) the BS may indicate/set, through the SIB, which of Alt 4-2-1and Alt 4-2-2 is to be applied as a condition for allowing the CPextension and/or whether the CP extension is allowed.

Additionally, depending on whether the UE supports the CP extension, theCP extension operation may not be performed. That is, even when the BSindicates/sets the CP extension operation through SIB1, the UE may failto follow the contents related to the CP extension indicated by the BSunless the UE capability supports the CP extension operation. When theUE does not support the CP extension, 4-step RACH may be used instead of2-step RACH.

3.5 Embodiment 5: Frequency Offsets for FDMed ROs in NR-U

When the PRACH uses a 30 kHz SCS, a length-571 Zadoff-Chu (ZC) sequencemay be used as the PRACH preamble sequence. When the PRACH uses a 15 kHzSCS, a Length-1151 ZC sequence may be used as the PRACH preamblesequence. In addition, FDM of RO may be configured in NR-U. According tothe conventional system, the number of FDMed ROs is indicated by theparameter msg1-FDM (=1, 2, 4, 8), and the starting frequency position ofthe RO positioned at the lowest frequency among the FDMed ROs isindicated by the parameter msg1-FrequencyStart (PRB level offset).

However, a UL active BWP may be indicated as including one or multipleRB sets. A UL active BWP including multiple RB sets may include anintra-cell guard PRB. When multiple ROs are configured by FDM,intra-cell guard PRBs in the UL active BWP may be positioned in themiddle of the ROs, which is inappropriate to transmission of a PRACHsequence.

Therefore, multiple FDMed ROs may be configured to be present one ineach UL RB set, and the following solutions are proposed.

[Proposed Method 5-1]: The starting frequency position of multiple FDMedROs may be configured to start based on the lowest PRB of each UL RBset.

Opt 5-1-1) In addition to method 1 above, the starting frequencyposition of each RO may be commonly indicated using an existingparameter (i.e., msg1-Frequency Start). For example, the startingfrequency position of each RO may be set to a position obtained byadding a value of a single offset parameter to the lowest PRB in each ULRB set. The single offset parameter may be msg1-FrequencyStart. Thesingle offset parameter may be applied to all UL RB sets in common.

Opt 5-1-2) In addition to method 1 above, an independent parameter maybe added for each RO to independently indicate the starting frequencyposition of each RO. For example, the starting frequency position ofeach RO may be set to a position obtained by adding the value of anoffset parameter set individually/independently (for each UL RB set) tothe lowest PRB in each UL RB set. The offset parameter that is setindividually/independently may be msg1-FrequencyStart. The frequencyoffset may be in units of PRBs or REs (subcarriers).

Opt 5-1-3) Parameter S (i.e., msg1-FrequencyStart) for the startingposition of the RO positioned at the lowest frequency in the UL activeBWP, and parameter N for the number of ROs FDMed in the frequency domainmay be configured through higher layer signaling (e.g. SIB, RRC). Thegap between the starting PRB index (corresponding to the value ofparameter S) of the RO positioned at the lowest frequency and the lowestPRB index in the UL RB set including the RO positioned at the lowestfrequency is defined as the RO offset (e.g. RO offset=R). The set indexof the UL RB set including the RO positioned at the lowest frequency maybe A. The remaining N−1 ROs are allocated to N−1 UL RB sets that areconsecutive in frequency after the UL RB set A including the ROpositioned at the lowest frequency, respectively. For the N−1 ROsallocated to the N−1 UL RB sets, the RO offset value, R is equallyapplied as the gap between the lowest PRB index in each UL RB set andthe starting PRB index of the RO included in each UL RB set.

When a specific PRACH preamble sequence (having, for example, a shortlength) is configured and multiple ROs consecutive in terms of frequencywithin a UL RB set are allocable, the RO offset R is equally applied tothe RO positioned at the lowest frequency in each UL RB set by Opt5-1-3. Multiple ROs consecutive in the frequency domain are allocatedfrom the RO positioned at the lowest frequency in each UL RB set. Themaximum number of the multiple ROs may be set to the maximum number ofROs that may be completely included in the UL RB set while beingconsecutive from the RO positioned at the lowest frequency in each UL RBset. After ROs consecutive in the frequency domain are allocated in eachUL RB set starting with the UL RB set A including the RO positioned atthe lowest frequency, ROs may be allocated to each of UL RB setsconsecutive in the frequency domain.

Opt 5-1-4) Parameter S (i.e., msg1-FrequencyStart) for the startingposition of the RO positioned at the lowest frequency in the UL activeBWP, and parameter N for the number of ROs FDMed in the frequency domainmay be configured through higher layer signaling (e.g. SIB, RRC). Thegap between the starting PRB index (corresponding to the value ofparameter S) of the RO positioned at the lowest frequency and the lowestPRB index in the UL RB set including the RO positioned at the lowestfrequency is defined as the RO offset. The set index of the UL RB setincluding the RO positioned at the lowest frequency may be A. The ROoffset is applied only to the RO positioned at the lowest frequency. Theremaining N−1 ROs are allocated to N−1 UL RB sets that are consecutivein frequency after the UL RB set A including the RO positioned at thelowest frequency, respectively. For the N−1 ROs allocated to the N−1 ULRB sets, the lowest PRB index in each UL RB set is set to the startingPRB index of the RO included in the UL RB set (i.e., RO offset=0).

When a specific PRACH preamble sequence (having, for example, a shortlength) is configured and multiple ROs consecutive in terms of frequencywithin a UL RB set are allocable, the RO offset R or 0 is applied to theRO positioned at the lowest frequency in each UL RB set by Opt 5-1-4.Multiple ROs consecutive in the frequency domain are allocated from theRO positioned at the lowest frequency in each UL RB set. The maximumnumber of the multiple ROs may be set to the maximum number of ROs thatmay be completely included in the UL RB set while being consecutive fromthe RO positioned at the lowest frequency in each UL RB set. After ROsconsecutive in the frequency domain are allocated in each UL RB setstarting with the UL RB set A including the RO positioned at the lowestfrequency, ROs may be allocated to each of UL RB sets consecutive in thefrequency domain.

The RB set assumed by the UE in Proposed Method 5-1 may be an RB setbased on the nominal guard band defined in the RAN4 spec, not the RB setbased on a guard band configured through RRC. Based on this RB setconfiguration, the PRACH mapping method in Proposed Method 5-1 may becarried out/applied.

[Proposed Method 5-2]: A parameter indicating a gap between multipleFDMed ROs may be added.

The starting frequency position of the RO positioned at the lowestfrequency among the multiple ROs subjected to FDM may be indicated usingan existing parameter (i.e., msg1-FrequencyStart). The startingfrequency position of the next RO is a position separated by a specificfrequency offset from the highest frequency position occupied by theimmediately preceding RO using the added parameter. The frequency offsetmay be in units of PRBs or REs (subcarriers).

The RB set assumed by the UE in Proposed Method 5-2 may be an RB setbased on the nominal guard band defined in the RAN4 spec, not an RB setbased on a guard band configured through RRC. Based on this RB setconfiguration, the PRACH mapping method in Proposed Method 5-1 may becarried out/applied.

Proposed Methods 5-1 and 5-2 may be applied regardless of the presenceor absence of the intra-cell guard PBR in the UL active BWP.Additionally, Proposed Methods 5-1 and 5-2 may be applied only when theintra-cell guard PRB is present in the UL active BWP. Proposed Methods5-1 and 5-2 may be configured to be applied only when the intra-cellguard PRB is present in the active BWP. In this case, the configurationof the conventional system may be applied when the intra-cell guard PRBis not present in the UL active BWP.

3.6 Embodiment 6: Guard Band for PUSCH Transmission in RACH Procedure

When a PUSCH (i.e., Msg. 3 PUSCH (or Msg. A PUSCH)) is transmitted inthe RACH procedure, the number and positions of PRBs in which the PUSCHis transmitted may differ between UEs depending on whether the UEs haveacquired guard band configuration information.

As an example, an idle mode UE that has failed to acquire the guard bandconfiguration information may recognize that PRBs based on the nominalguard band information are the guard band and determine an RB set range.A connected mode UE that has acquired the guard band configurationinformation may determine the RB set range by checking the guard bandconfiguration information acquired from the BS. In this case, the RBsets ranges configured by the two UEs may be different from each otheraccording to the guard band information configured by the BS.Accordingly, Msg. 3 PUSCH (or Msg. A PUSCH) may be transmitted on a ULresource (e.g., interlaced PRB) composed of a different number of PRBsfor each UE. Therefore, the BS may need to address the issue of blinddecoding (BD) in those two cases.

Therefore, the UE and the BS may be configured to determine that the RBset is configured according to the nominal guard band information whenMsg. 3 PUSCH (or Msg. A PUSCH) is transmitted. Transmitting the Msg. 3PUSCH (or Msg. A PUSCH) corresponds to a case where PUSCH indicated bythe RAR grant, PUSCH scheduled by DCI 0_0 scrambled with TC-RNTI, orMsg. A PRACH is transmitted, and then Msg. A PUSCH is transmitted on thePO associated with the corresponding RO. The UE and the BS may operateto transmit and receive Msg. 3 PUSCH (or Msg. A PUSCH) using only thePRB resources in the corresponding RB set based on the RB set in whichthe nominal guard band is configured. When they are configured in thisway, the BS may not need to perform BD when receiving the Msg. 3 PUSCH(or Msg. A PUSCH).

Specifically, the proposed method above may be applied in contentionbased random access (CBRA). In other words, since the RACH procedure isperformed based on contention between multiple UEs, Msg. 3 PUSCH (orMsg. A PUSCH) is also transmitted from multiple UEs in an overlappingmanner. Therefore, in order not to increase the BD complexity of the BS,the Msg. 3 PUSCH (or Msg. A PUSCH) may be configured to be transmittedon a UL resource (e.g., interlaced PRB) composed of the same number ofPRBs.

In a situation in which the BS has issued an order of operation incontention free random access (CFRA) through a PDCCH order, the BS mayseparately specify a random access preamble ID (RAPID) for CFRA to aspecific UE operating in the connected mode. At this time, the BSalready recognizes that only the specific UE to which the BS has issuedthe order will transmit (Msg. 3) PUSCH indicated by the RAR grantcorresponding to the RAPID (or Msg. A PUSCH associated with the Msg. APRACH corresponding to the RAPID). Accordingly, the BS may determinethat the specific UE already knows the guard band and RB setconfiguration information through the guard band configurationinformation indicated by the BS. Accordingly, the BS does not need toconfigure that the specific UE is to unnecessarily configure an RB setaccording to the nominal guard band information. Therefore, the UEinstructed to perform CFRA (through the PDCCH order) may transmit the(Msg. 3) PUSCH indicated by the RAR grant corresponding to the RAPIDindicated by the BS (or Msg. A PUSCH associated with the Msg. A PRACHcorresponding to the RAPID indicated by the BS), determining that the RBset is configured according to the guard band configuration informationindicated by the BS. Accordingly, the UE and the BS may operate totransmit and receive Msg. 3 PUSCH (or Msg. A PUSCH) using only the PRBresources in the corresponding RB set based on the RB set in which theguard band is configured.

Additionally, an issue similar to that described above may be raisedregarding the PRACH (Msg. 1 preamble or Msg. A PRACH). That is, inrelation to the method of Embodiment 5 proposing that the operationshould proceed to the next RB set when multiple ROs are allocated in thefrequency domain and a specific RO occupies multiple RB sets, the UE andthe BS need to exactly identify the starting PRB index of the next RBset. The idle mode UE, which has failed to receive the UE-specific guardband configuration, checks the RB set configuration according to thenominal guard band, while the connected mode UE, which may receive theUE-specific guard band configuration, checks the RB set configuration asindicated by the BS. If the RB set configurations understood by the twoUEs are different from each other, the position of the actual RO mayalso differ between the UEs, raising an issue in terms of BS reception.

Therefore, when Msg. 1 PRACH (or Msg. A PRACH) is transmitted, the UEand the BS may be configured to always determine that the RB set isconfigured according to the nominal guard band information. Accordingly,the UE and the BS may operate to transmit and receive Msg. 1 PRACH (orMsg. A PRACH) using only the PRB resources in the corresponding RB setbased on the RB set in which the nominal guard band is configured.Alternatively, in configures/indicates an RO for transmitting Msg. 1PRACH (or Msg. A PRACH), the BS may configure the RO, always assumingthat the RB set is configured according to the nominal guard bandinformation. With the configuration established in this way, BD is notrequired when the BS receives the Msg. 1 PRACH (or Msg. A PRACH).

Additionally, the proposed method described above may be equally appliedto transmission of PUCCH (i.e., initial PUCCH resource set) throughwhich HARQ ACK of Msg. 4 or Msg. B is transmitted. In other words, whena PUCCH for transmitting HARQ ACK PUCCH of Msg. 4 or HARQ ACK PUCCH ofMsg. B is transmitted (namely, when the initial PUCCH resource set isused before a dedicated PUCCH resource set is indicated), the UE and theBS may be configured to always determine that the RB set is configuredaccording to the nominal guard band information. Accordingly, the UE andthe BS may operate to transmit and receive the HARQ ACK PUCCH of Msg. 4or the HARQ ACK PUCCH of Msg. B using only the PRB resources in thecorresponding RB set based on the RB set in which the nominal guard bandis configured. Further, with the above method, BD is not required whenthe BS receives the HARQ ACK PUCCH of Msg. 4 or the HARQ ACK PUCCH ofMsg. B.

3.7 Embodiment 7: PO Allocation for 2-Step RACH Procedure in NR-U

When the 2-step RACH procedure is used in NR-U, the BS may configure aPUSCH occasion (PO) using UL resource allocation type 2 (interlacedstructure). The BS may configure/indicate multiple FDMed POs using thefollowing methods.

[Proposed Method 7-1] When multiple interlace indexes and multiple RBsets are configured, PO indexing may be performed.

It is assumed that the BWP is composed of K RB sets, and a total of L(unit) interlaces are configured in each RB set (where K and L arenatural numbers).

The UE and the BS index a total of {K×L} (unit) interlace resources inthe lowest (or highest) index order in the RB interlace index first & RBset index second manner (where m=0, 1, . . . , K×L−1).

As an example, the UE and the BS index {interlace index 0 in RB setindex 0} as (unit) interlace index 0, {interlace index 1 in RB set index0} as (unit) interlace index 1, . . . , {interlace index L−1 in RB setindex 0} as (unit) interlace index L−1, {interlace index 0 in RB setindex 1} as (unit) interlace index L, {interlace index 1 in RB set index1} as (unit) interlace index L+1, . . . , and {interlace index L−1 in RBset index K−1} as (unit) interlace index K×L−1.

For the BWP, three parameters, that is, starting (unit) interlace index(or offset) “A”, number of (unit) interlaces per PO “B”, and number ofFDMed POs “C” may be configured for the UE through SIB or RRC.

Accordingly, B adjacent (unit) interlaces (on the (unit) interlace indexm) starting from (unit) interlace index m=A may be bundled to form eachPO resource. Thereby, a total of C POs (adjacent on the (unit) interlaceindex m) may be configured.

For example, m=A to A+B−1 may be set to the first PO (PO index 0), m=A+Bto A+2B−1 may be set to the second PO (PO index 1), . . . , andm=A+(C−1)×B to A+C×B−1 may be set to the last C-th PO (PO index C−1).

According to the confirmation described above, POs may be configuredusing all the (unit) interlace indexes for each single RB set length.Accordingly, the number of occasions for transmitting Msg. A PUSCH maybe increased, and thus the BS may be configured with ease in RO to POmapping.

Additionally, the gap between the lowest (unit) interlace index in theRB set to which the starting (unit) interlace index (or offset) “A”configured by the BS belongs (e.g., the first RB set in which the POresource is configured) and the starting (unit) interlace index (oroffset) “A” may be determined as the interlace index offset. Inaddition, the interlace index offset may be applied even to other RBsets (after the first RB set (index)) (for the (first) PO resourceconfigured in the RB sets).

For example, when a total of 5 (unit) interlace indexes are present inan RB set, A is set to (unit) interlace index 6, and B is set to 2(unit) interlaces, {interlace index 1/2 in RB set index 1} is set to POindex 0 (in this case, the interlace index offset=1, and therefore theoffset is equally applied to RB sets after RB set index 1), {interlaceindex 3/4 in RB set index 1} is set to PO index 1, {interlace index 1/2in RB set index 2} is set to PO index 2, and the like.

[Proposed Method 7-2] A single RO may be additionally configured toalways be included in a single RB set based on Proposed Method 7-1.

As in Proposed Method 7-1, it is assumed that the BWP is composed of KRB sets and a total of L (unit) interlaces are configured in each of theRB sets (where K and L are natural numbers).

In this case, the UE and the BS index a total of {K×L} (unit) interlaceresources in the lowest (or highest) index order in the RB interlaceindex first & RB set index second manner (where m=0, 1, K×L−1).

As an example, the UE and the BS index {interlace index 0 in RB setindex 0} as (unit) interlace index 0, {interlace index 1 in RB set index0} as (unit) interlace index 1, . . . , {interlace index L−1 in RB setindex 0} as (unit) interlace index L−1, {interlace index 0 in RB setindex 1} as (unit) interlace index L, {interlace index 1 in RB set index1} as (unit) interlace index L+1, . . . , and {interlace index L−1 in RBset index K−1} as (unit) interlace index K×L−1.

In addition, For the BWP, three parameters, that is, starting (unit)interlace index (or offset) “A”, number of (unit) interlaces per PO “B”,and number of FDMed POs “C” may be configured for the UE through SIB orRRC.

Accordingly, B adjacent (unit) interlaces (on the (unit) interlace indexm) starting from (unit) interlace index m=A may be bundled to form eachPO resource. Thereby, a total of C POs (adjacent on the (unit) interlaceindex m) may be configured.

For example, m=A to A+B−1 may be set to the first PO (PO index 0), m=A+Bto A+2B−1 may be set to the second PO (PO index 1), . . . , andm=A+(C−1)×B to A+C×B−1 may be set to the last C-th PO (PO index C−1).

Additionally, when one PO is composed of B adjacent (unit) interlaces on(unit) interlace index m, if the corresponding PO resource spansmultiple RB sets (e.g., two RB sets having indexes k and k+1), the POmay be composed of B adjacent (unit) interlaces, starting from the first(unit) interlace index of the RB set having the highest frequency orindex between the multiple RB sets (RB set index k+1 in the case of thepreceding example).

For example, in the configuration of Proposed Method 7-1, when a totalof 5 (unit) interlace indexes are present in an RB set, A is set to(unit) interlace index 0, and B is set to 2 (unit) interlaces,{interlace index 0/1 in RB set index 0} is set to PO index 0, {interlaceindex 2/3 in RB set index 0} is set to PO index 1, {interlace index 4 inRB set index 0 & interlace index 0 in RB set index 1} is set to PO index2, and the like.

For example, in the configuration of Proposed Method 7-2, when a totalof 5 (unit) interlace indexes are present in an RB set, A is set to(unit) interlace index 0, and B is set to 2 (unit) interlaces,{interlace index 0/1 in RB set index 0} may be set to PO index 0,{interlace index 2/3 in RB set index 0} may be set to PO index 1,{interlace index 0/1 in RB set index 1} may be set to PO index 2, andthe like.

When configuration is established as described above, all POs may belimited in one RB set, and therefore the probability that the UE willsucceed in LBT may be increased.

Additionally, the gap between the lowest (unit) interlace index in theRB set to which the starting (unit) interlace index (or offset) “A”configured by the BS belongs (e.g., the first RB set in which the POresource is configured) and the starting (unit) interlace index (oroffset) “A” may be determined as the interlace index offset. Inaddition, the interlace index offset may be applied even to other RBsets (after the first RB set (index)) (for the (first) PO resourceconfigured in the RB sets).

For example, a total of 5 (unit) interlace indexes exist in the RB set,A is set to (unit) interlace index 7, and B is set to 2 (unit)interlaces, {interlace index 2/3 in RB set index 1} may be set to POindex 0 (in this case, the interlace index offset=2, and therefore theoffset is equally applied to RB sets after RB set index 1), {interlaceindex 2/3 in RB set index 2} may be set to PO index 1, {interlace index2/3 in RB set index 3} may be set to PO index 2, and the like.

Discontinuous Reception (DRX) Operation

The UE may perform a DRX operation, while performing theafore-described/proposed procedures and/or methods. A UE configured withDRX may reduce power consumption by discontinuously receiving a DLsignal. DRX may be performed in an RRC IDLE state, an RRC_INACTIVEstate, and an RRC_CONNECTED stated. DRX is used for discontinuousreception of a paging signal in the RRC IDLE state and the RRC_INACTIVEstate. Now, DRX performed in the RRC_CONNECTED state (RRC_CONNECTED DRX)will be described below.

FIG. 17 is a diagram illustrating a DRX cycle (RRC_CONNECTED state).

Referring to FIG. 17 , the DRX cycle includes On Duration andOpportunity for DRX. The DRX cycle defines a time interval in which OnDuration is periodically repeated. On Duration is a time period duringwhich the UE monitors to receive a PDCCH. When DRX is configured, the UEperforms PDCCH monitoring during the On Duration. When there is anysuccessfully detected PDCCH during the PDCCH monitoring, the UE operatesan inactivity timer and is maintained in an awake state. On the otherhand, when there is no successfully detected PDCCH during the PDCCHmonitoring, the UE enters a sleep state, when the On Duration ends.Therefore, if DRX is configured, PDCCH monitoring/reception may beperformed discontinuously in the time domain, when theafore-described/proposed procedures and/or methods are performed. Forexample, if DRX is configured, PDCCH reception occasions (e.g., slotshaving PDCCH search spaces) may be configured discontinuously accordingto a DRX configuration in the present disclosure. On the contrary, ifDRX is not configured, PDCCH monitoring/reception may be performedcontinuously in the time domain, when the afore-described/proposedprocedures and/or methods are performed. For example, if DRX is notconfigured, PDCCH reception occasions (e.g., slots having PDCCH searchspaces) may be configured continuously in the present disclosure. PDCCHmonitoring may be limited in a time period configured as a measurementgap, irrespective of whether DRX is configured.

Table 16 describes a UE operation related to DRX (in the RRC_CONNECTEDstate). Referring to Table 16, DRX configuration information is receivedby higher-layer (RRC) signaling, and DRX ON/OFF is controlled by a DRXcommand of the MAC layer. Once DRX is configured, the UE may performPDCCH monitoring discontinuously in performing the described/proposedprocedures and/or methods according to the present disclosure, asillustrated in FIG. 17 .

TABLE 16 Type of signals UE procedure 1^(st) step RRC signalling ReceiveDRX configuration (MAC- information CellGroupConfig) 2^(nd) Step MAC CEReceive DRX command ((Long) DRX command MAC CE) 3^(rd) Step — Monitor aPDCCH during an on- duration of a DRX cycle

MAC-CellGroupConfig includes configuration information required toconfigure MAC parameters for a cell group. MAC-CellGroupConfig may alsoinclude DRX configuration information. For example, MAC-CellGroupConfigmay include the following information in defining DRX.

-   -   Value of drx-OnDurationTimer: defines the length of the starting        duration of a DRX cycle.    -   Value of drx-InactivityTimer: defines the length of a time        duration in which the UE is in the awake state after a PDCCH        occasion in which a PDCCH indicating initial UL or DL data has        been detected.    -   Value of drx-HARQ-RTT-TimerDL: defines the length of a maximum        time duration from reception of a DL initial transmission to        reception of a DL retransmission.    -   Value of drx-HARQ-RTT-TimerDL: defines the length of a maximum        time duration from reception of a grant for a DL initial        transmission to reception of a grant for a UL retransmission.    -   drx-LongCycleStartOffset: defines the time duration and starting        time of a DRX cycle.    -   drx-ShortCycle (optional): defines the time duration of a short        DRX cycle.

When at least one of drx-OnDurationTimer, drx-InactivityTimer,drx-HARQ-RTT-TimerDL, or drx-HARQ-RTT-TimerDL is running, the UEperforms PDCCH monitoring in each PDCCH occasion, while staying in theawake state.

After the operation described in each embodiment of the presentdisclosure, the UE may perform such a DRX-related operation. Afterperforming the RACH procedure according to an embodiment of the presentdisclosure, the UE may monitor a PDCCH for an On duration. When there isa PDCCH successfully detected during the PDCCH monitoring, the UE mayoperate an inactivity timer (drx-InactivityTimer) and stay awake.

Implementation Examples

FIG. 18 is a flowchart illustrating a signal transmission/receptionmethod according to embodiments of the present disclosure.

Referring to FIG. 18 , the embodiments of the present disclosure may becarried out by a UE, and may include performing an RACH procedure(S1801), after performing the RACH procedure, monitoring a PDCCH for anon duration based on a configured DRX operation (S1803), and starting aninactivity timer and staying awake based on the successfully receivedPDCCH for the on duration (S1805).

The RACH procedure includes a 4-step RACH procedure and a 2-step RACHprocedure.

During the RACH procedure, the PRACH may be transmitted on a specificRACH occasion (RO) among a plurality of ROs. In addition, the PRACH maybe transmitted on some specific ROs among the plurality of ROs.

The plurality of ROs may be configured by a combination of one or moreof the methods described in Embodiments 1 to 7.

For example, when the plurality of ROs is configured based on Embodiment5, the ROs may be included in uplink RB sets, respectively, one for eachof the uplink RB sets. In addition, the uplink RB sets may be includedin one uplink active BWP. In other words, one uplink active BWP mayinclude a plurality of RB sets, and a guard band (or guard PRB) may bepresent between the RB sets. Also, each of the RB sets may include oneRO. Accordingly, the number of RB sets and the number of ROs are thesame in one uplink active BWP.

As a more specific example, when a plurality of ROs is configured basedon Opt 5-1-3 of Proposed Method 5-1, the starting RB index of a specificRO included in the plurality of ROs may be determined based on (i) thelowest RB index of a RB set including the specific RO, (ii) the startingRB index of a RO positioned at the lowest frequency, and (iii) thelowest RB index of a RB set including the RO positioned at the lowestfrequency.

More specifically, the value of the starting RB index of the specific ROis obtained by adding the value of the lowest RB index of the RB setincluding the specific RO and an offset value. The offset value may beobtained by subtracting the value of the lowest RB index of the RB setincluding the RO positioned at the lowest frequency from the value ofthe starting RB index of the RO positioned at the lowest frequency.

The starting RB index of each of all the plurality of ROs including thespecific RO may be determined based on (i) the lowest RB index of eachRB set including each RO, (ii) the starting RB index of the ROpositioned at the lowest frequency, and (iii) the lowest RB index of theRB set including the RO positioned at the lowest frequency.

In response to the PRACH, the UE may receive the RAR. After the RAR isreceived, the PUSCH included in Msg. 3 may be transmitted.Alternatively, Msg. A PUSCH included in the same Msg. A as the PRACH maybe transmitted. A PO on which Msg. A PUSCH is transmitted may also beconfigured by a combination of one or more of the methods described inEmbodiments1 to 7.

Regarding the guard band positioned between the RB sets, the guard bandmay be configured based on Embodiment 6.

For example, according to Embodiment 6, even when UE-specific guard bandinformation for each uplink RB set is received, the plurality of ROs maybe configured on a basis that each uplink RB set is configured based onnominal guard band information.

Even when UE-specific guard band information for each uplink RB set isreceived, the plurality of POs may be configured on a basis that eachuplink RB set is configured based on the nominal guard band information.A PUCCH including HARQ ACK transmitted by the UE in response toreception of Msg. 4 may be configured on a basis that each uplink RB setis configured based on the nominal guard band information even when theUE-specific guard band information for each uplink RB set is received.

The methods of Opt 5-1-3 and Embodiment 6 may be carried out incombination with each other or may be carried out independently. Theoperations of Embodiments 1 to 7 may also be performed in combinationwith each other or may be performed independently.

In addition to the operations described with reference to FIG. 18 , oneor more of the operations described with reference to FIGS. 1 to 17and/or the operations described in Embodiments 1 to 7 may be combinedand additionally performed. For example, the UE may perform uplink LBTbefore transmitting the PRACH. In addition, the UE may receive an RMSIincluding information about the PRACH before transmitting the PRACH.

Example of Communication System to which the Present Disclosure isApplied

The various descriptions, functions, procedures, proposals, methods,and/or operation flowcharts of the present disclosure described hereinmay be applied to, but not limited to, various fields requiring wirelesscommunication/connectivity (e.g., 5G) between devices.

More specific examples will be described below with reference to thedrawings. In the following drawings/description, like reference numeralsdenote the same or corresponding hardware blocks, software blocks, orfunction blocks, unless otherwise specified.

FIG. 19 illustrates a communication system 1 applied to the presentdisclosure.

Referring to FIG. 19 , the communication system 1 applied to the presentdisclosure includes wireless devices, BSs, and a network. A wirelessdevice is a device performing communication using radio accesstechnology (RAT) (e.g., 5G NR (or New RAT) or LTE), also referred to asa communication/radio/5G device. The wireless devices may include, notlimited to, a robot 100 a, vehicles 100 b-1 and 100 b-2, an extendedreality (XR) device 100 c, a hand-held device 100 d, a home appliance100 e, an IoT device 100 f, and an artificial intelligence (AI)device/server 400. For example, the vehicles may include a vehiclehaving a wireless communication function, an autonomous driving vehicle,and a vehicle capable of vehicle-to-vehicle (V2V) communication. Herein,the vehicles may include an unmanned aerial vehicle (UAV) (e.g., adrone). The XR device may include an augmented reality (AR)/virtualreality (VR)/mixed reality (MR) device and may be implemented in theform of a head-mounted device (HMD), a head-up display (HUD) mounted ina vehicle, a television (TV), a smartphone, a computer, a wearabledevice, a home appliance, a digital signage, a vehicle, a robot, and soon. The hand-held device may include a smartphone, a smart pad, awearable device (e.g., a smart watch or smart glasses), and a computer(e.g., a laptop). The home appliance may include a TV, a refrigerator, awashing machine, and so on. The IoT device may include a sensor, a smartmeter, and so on. For example, the BSs and the network may beimplemented as wireless devices, and a specific wireless device 200 amay operate as a BS/network node for other wireless devices.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f, and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without intervention of theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g., V2V/vehicle-to-everything (V2X)communication). The IoT device (e.g., a sensor) may perform directcommunication with other IoT devices (e.g., sensors) or other wirelessdevices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, and 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200 andbetween the BSs 200. Herein, the wireless communication/connections maybe established through various RATs (e.g., 5G NR) such as UL/DLcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter-BS communication (e.g., relay or integratedaccess backhaul (IAB)). Wireless signals may be transmitted and receivedbetween the wireless devices, between the wireless devices and the BSs,and between the BSs through the wireless communication/connections 150a, 150 b, and 150 c. For example, signals may be transmitted and receivedon various physical channels through the wirelesscommunication/connections 150 a, 150 b and 150 c. To this end, at leasta part of various configuration information configuring processes,various signal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocation processes, for transmitting/receiving wireless signals, maybe performed based on the various proposals of the present disclosure.

Example of Wireless Device to which the Present Disclosure is Applied

FIG. 20 illustrates wireless devices applicable to the presentdisclosure.

Referring to FIG. 20 , a first wireless device 100 and a second wirelessdevice 200 may transmit wireless signals through a variety of RATs(e.g., LTE and NR). {The first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. 19 . The first wireless device 100 may include one ormore processors 102 and one or more memories 104, and further includeone or more transceivers 106 and/or one or more antennas 108. Theprocessor(s) 102 may control the memory(s) 104 and/or the transceiver(s)106 and may be configured to implement the descriptions, functions,procedures, proposals, methods, and/or operation flowcharts disclosed inthis document. For example, the processor(s) 102 may process informationin the memory(s) 104 to generate first information/signals and thentransmit wireless signals including the first information/signalsthrough the transceiver(s) 106. The processor(s) 102 may receivewireless signals including second information/signals through thetransceiver(s) 106 and then store information obtained by processing thesecond information/signals in the memory(s) 104. The memory(s) 104 maybe connected to the processor(s) 102 and may store various pieces ofinformation related to operations of the processor(s) 102. For example,the memory(s) 104 may store software code including instructions forperforming all or a part of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operation flowcharts disclosed in this document. Theprocessor(s) 102 and the memory(s) 104 may be a part of a communicationmodem/circuit/chip designed to implement RAT (e.g., LTE or NR). Thetransceiver(s) 106 may be connected to the processor(s) 102 and transmitand/or receive wireless signals through the one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with radiofrequency (RF) unit(s). In the present disclosure, the wireless devicemay be a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204, and further include one or moretransceivers 206 and/or one or more antennas 208. The processor(s) 202may control the memory(s) 204 and/or the transceiver(s) 206 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operation flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process information inthe memory(s) 204 to generate third information/signals and thentransmit wireless signals including the third information/signalsthrough the transceiver(s) 206. The processor(s) 202 may receivewireless signals including fourth information/signals through thetransceiver(s) 106 and then store information obtained by processing thefourth information/signals in the memory(s) 204. The memory(s) 204 maybe connected to the processor(s) 202 and store various pieces ofinformation related to operations of the processor(s) 202. For example,the memory(s) 204 may store software code including instructions forperforming all or a part of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operation flowcharts disclosed in this document. Theprocessor(s) 202 and the memory(s) 204 may be a part of a communicationmodem/circuit/chip designed to implement RAT (e.g., LTE or NR). Thetransceiver(s) 206 may be connected to the processor(s) 202 and transmitand/or receive wireless signals through the one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may be acommunication modem/circuit/chip.

Now, hardware elements of the wireless devices 100 and 200 will bedescribed in greater detail. One or more protocol layers may beimplemented by, not limited to, one or more processors 102 and 202. Forexample, the one or more processors 102 and 202 may implement one ormore layers (e.g., functional layers such as physical (PHY), mediumaccess control (MAC), radio link control (RLC), packet data convergenceprotocol (PDCP), RRC, and service data adaptation protocol (SDAP)). Theone or more processors 102 and 202 may generate one or more protocoldata units (PDUs) and/or one or more service data Units (SDUs) accordingto the descriptions, functions, procedures, proposals, methods, and/oroperation flowcharts disclosed in this document. The one or moreprocessors 102 and 202 may generate messages, control information, data,or information according to the descriptions, functions, procedures,proposals, methods, and/or operation flowcharts disclosed in thisdocument and provide the messages, control information, data, orinformation to one or more transceivers 106 and 206. The one or moreprocessors 102 and 202 may generate signals (e.g., baseband signals)including PDUs, SDUs, messages, control information, data, orinformation according to the descriptions, functions, procedures,proposals, methods, and/or operation flowcharts disclosed in thisdocument and provide the generated signals to the one or moretransceivers 106 and 206. The one or more processors 102 and 202 mayreceive the signals (e.g., baseband signals) from the one or moretransceivers 106 and 206 and acquire the PDUs, SDUs, messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operation flowchartsdisclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. For example, one or moreapplication specific integrated circuits (ASICs), one or more digitalsignal processors (DSPs), one or more digital signal processing devices(DSPDs), one or more programmable logic devices (PLDs), or one or morefield programmable gate arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operation flowcharts disclosed in thisdocument may be implemented using firmware or software, and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operation flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or may be stored in the one or more memories 104 and 204 andexecuted by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operation flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, an instruction, and/or a set of instructions.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured to includeread-only memories (ROMs), random access memories (RAMs), electricallyerasable programmable read-only memories (EPROMs), flash memories, harddrives, registers, cash memories, computer-readable storage media,and/or combinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or wireless signals/channels, mentioned in the methodsand/or operation flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or wireless signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperation flowcharts disclosed in this document, from one or more otherdevices. For example, the one or more transceivers 106 and 206 may beconnected to the one or more processors 102 and 202 and transmit andreceive wireless signals. For example, the one or more processors 102and 202 may perform control so that the one or more transceivers 106 and206 may transmit user data, control information, or wireless signals toone or more other devices. The one or more processors 102 and 202 mayperform control so that the one or more transceivers 106 and 206 mayreceive user data, control information, or wireless signals from one ormore other devices. The one or more transceivers 106 and 206 may beconnected to the one or more antennas 108 and 208 and the one or moretransceivers 106 and 206 may be configured to transmit and receive userdata, control information, and/or wireless signals/channels, mentionedin the descriptions, functions, procedures, proposals, methods, and/oroperation flowcharts disclosed in this document, through the one or moreantennas 108 and 208. In this document, the one or more antennas may bea plurality of physical antennas or a plurality of logical antennas(e.g., antenna ports). The one or more transceivers 106 and 206 mayconvert received wireless signals/channels from RF band signals intobaseband signals in order to process received user data, controlinformation, and wireless signals/channels using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, and wirelesssignals/channels processed using the one or more processors 102 and 202from the baseband signals into the RF band signals. To this end, the oneor more transceivers 106 and 206 may include (analog) oscillators and/orfilters.

Example of Use of Wireless Device to which the Present Disclosure isApplied

FIG. 21 illustrates another example of a wireless device applied to thepresent disclosure. The wireless device may be implemented in variousforms according to a use case/service (refer to FIG. 19 ).

Referring to FIG. 21 , wireless devices 100 and 200 may correspond tothe wireless devices 100 and 200 of FIG. 20 and may be configured toinclude various elements, components, units/portions, and/or modules.For example, each of the wireless devices 100 and 200 may include acommunication unit 110, a control unit 120, a memory unit 130, andadditional components 140. The communication unit 110 may include acommunication circuit 112 and transceiver(s) 114. For example, thecommunication circuit 112 may include the one or more processors 102 and202 and/or the one or more memories 104 and 204 of FIG. 20 . Forexample, the transceiver(s) 114 may include the one or more transceivers106 and 206 and/or the one or more antennas 108 and 208 of FIG. 20 . Thecontrol unit 120 is electrically connected to the communication unit110, the memory 130, and the additional components 140 and providesoverall control to the wireless device. For example, the control unit120 may control an electric/mechanical operation of the wireless devicebased on programs/code/instructions/information stored in the memoryunit 130. The control unit 120 may transmit the information stored inthe memory unit 130 to the outside (e.g., other communication devices)via the communication unit 110 through a wireless/wired interface orstore, in the memory unit 130, information received through thewireless/wired interface from the outside (e.g., other communicationdevices) via the communication unit 110.

The additional components 140 may be configured in various mannersaccording to type of the wireless device. For example, the additionalcomponents 140 may include at least one of a power unit/battery,input/output (I/O) unit, a driving unit, and a computing unit. Thewireless device may be implemented in the form of, not limited to, therobot (100 a of FIG. 19 ), the vehicles (100 b-1 and 100 b-2 of FIG. 19), the XR device (100 c of FIG. 19 ), the hand-held device (100 d ofFIG. 19 ), the home appliance (100 e of FIG. 19 ), the IoT device (100 fof FIG. 19 ), a digital broadcasting terminal, a hologram device, apublic safety device, an MTC device, a medical device, a FinTech device(or a finance device), a security device, a climate/environment device,the AI server/device (400 of FIG. 19 ), the BSs (200 of FIG. 19 ), anetwork node, or the like. The wireless device may be mobile or fixedaccording to a use case/service.

In FIG. 21 , all of the various elements, components, units/portions,and/or modules in the wireless devices 100 and 200 may be connected toeach other through a wired interface or at least a part thereof may bewirelessly connected through the communication unit 110. For example, ineach of the wireless devices 100 and 200, the control unit 120 and thecommunication unit 110 may be connected by wire and the control unit 120and first units (e.g., 130 and 140) may be wirelessly connected throughthe communication unit 110. Each element, component, unit/portion,and/or module in the wireless devices 100 and 200 may further includeone or more elements. For example, the control unit 120 may beconfigured with a set of one or more processors. For example, thecontrol unit 120 may be configured with a set of a communication controlprocessor, an application processor, an electronic control unit (ECU), agraphical processing unit, and a memory control processor. In anotherexample, the memory 130 may be configured with a RAM, a dynamic RAM(DRAM), a ROM, a flash memory, a volatile memory, a non-volatile memory,and/or a combination thereof.

Example of Vehicle or Autonomous Driving Vehicle to which the PresentDisclosure is Applied

FIG. 22 illustrates a vehicle or an autonomous driving vehicle appliedto the present disclosure. The vehicle or autonomous driving vehicle maybe implemented as a mobile robot, a car, a train, a manned/unmannedaerial vehicle (AV), a ship, or the like.

Referring to FIG. 22 , a vehicle or autonomous driving vehicle 100 mayinclude an antenna unit 108, a communication unit 110, a control unit120, a driving unit 140 a, a power supply unit 140 b, a sensor unit 140c, and an autonomous driving unit 140 d. The antenna unit 108 may beconfigured as a part of the communication unit 110. The blocks110/130/140 a to 140 d correspond to the blocks 110/130/140 of FIG. 21 ,respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous driving vehicle 100. The control unit 120 mayinclude an ECU. The driving unit 140 a may enable the vehicle or theautonomous driving vehicle 100 to drive on a road. The driving unit 140a may include an engine, a motor, a powertrain, a wheel, a brake, asteering device, and so on. The power supply unit 140 b may supply powerto the vehicle or the autonomous driving vehicle 100 and include awired/wireless charging circuit, a battery, and so on. The sensor unit140 c may acquire information about a vehicle state, ambient environmentinformation, user information, and so on. The sensor unit 140 c mayinclude an inertial measurement unit (IMU) sensor, a collision sensor, awheel sensor, a speed sensor, a slope sensor, a weight sensor, a headingsensor, a position module, a vehicle forward/backward sensor, a batterysensor, a fuel sensor, a tire sensor, a steering sensor, a temperaturesensor, a humidity sensor, an ultrasonic sensor, an illumination sensor,a pedal position sensor, and so on. The autonomous driving unit 140 dmay implement technology for maintaining a lane on which the vehicle isdriving, technology for automatically adjusting speed, such as adaptivecruise control, technology for autonomously driving along a determinedpath, technology for driving by automatically setting a route if adestination is set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, and so on from an external server. The autonomousdriving unit 140 d may generate an autonomous driving route and adriving plan from the obtained data. The control unit 120 may controlthe driving unit 140 a such that the vehicle or autonomous drivingvehicle 100 may move along the autonomous driving route according to thedriving plan (e.g., speed/direction control). During autonomous driving,the communication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. Duringautonomous driving, the sensor unit 140 c may obtain information about avehicle state and/or surrounding environment information. The autonomousdriving unit 140 d may update the autonomous driving route and thedriving plan based on the newly obtained data/information. Thecommunication unit 110 may transfer information about a vehicleposition, the autonomous driving route, and/or the driving plan to theexternal server. The external server may predict traffic informationdata using AI technology based on the information collected fromvehicles or autonomous driving vehicles and provide the predictedtraffic information data to the vehicles or the autonomous drivingvehicles.

Those skilled in the art will appreciate that the present disclosure maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent disclosure. The above embodiments are therefore to be construedin all aspects as illustrative and not restrictive. The scope of thedisclosure should be determined by the appended claims and their legalequivalents, not by the above description, and all changes coming withinthe meaning and equivalency range of the appended claims are intended tobe embraced therein.

As described above, the present disclosure is applicable to variouswireless communication systems.

What is claimed is:
 1. A method for transmitting and receiving signalsby a user equipment (UE) operating in a wireless communication system,the method comprising: transmitting a message A including a physicalrandom access channel (PRACH) and a physical uplink shared channel(PUSCH); and receiving a message B based on the message A, wherein thePRACH is transmitted on a specific PRACH occasion (RO) and the PUSCH istransmitted on a specific PUSCH occasion (PO), wherein a startingresource block (RB) index for the specific RO is determined by adding(i) a value of a lowest RB index of a first RB set including thespecific RO and (ii) an offset value, wherein the offset value isobtained by subtracting (i) a value of a lowest RB index of a second RBset including a lowest RO in a frequency domain from (ii) a value of astarting RB index of the lowest RO in the frequency domain, and whereinthe specific RO and the lowest RO in the frequency domain are frequencydivision multiplexed (FDMed), and there is an intra-cell guard bandbetween the first RB set and the second RB set.
 2. The method of claim1, wherein a minimum gap size of the specific RO and the specific PO is2 symbols based on 15 or 30 kHz of Subcarrier Spacing (SCS), and theminimum gap size is 4 symbols based on 60 kHz SCS.
 3. The method ofclaim 1, wherein the transmission of the message A and the reception ofthe message B are included in a 2-step random access channel (RACH)procedure.
 4. The method of claim 1, wherein the PUSCH is transmittedthrough an interlace.
 5. The method of claim 1, wherein the specific POis selected among POs mapped to the specific RO.
 6. A user equipment(UE) for transmitting and receiving signals in a wireless communicationsystem, the UE comprising: at least one transceiver; at least oneprocessor; and at least one memory operatively coupled to the at leastone processor and configured to store instructions that, when executed,cause the at least one processor to perform specific operations, whereinthe specific operations comprise: transmitting a message A including aphysical random access channel (PRACH) and a physical uplink sharedchannel (PUSCH); and receiving a message B based on the Message A,wherein the PRACH is transmitted on a specific PRACH occasion (RO) andthe PUSCH is transmitted on a specific PUSCH occasion (PO), wherein astarting resource block (RB) index for the specific RO is determined byadding (i) a value of a lowest RB index of a first RB set including thespecific RO and (ii) an offset value, wherein the offset value isobtained by subtracting (i) a value of a lowest RB index of a second RBset including a lowest RO in a frequency domain from (ii) a value of astarting RB index of the lowest RO in the frequency domain, and whereinthe specific RO and the lowest RO in the frequency domain are frequencydivision multiplexed (FDMed), and there is an intra-cell guard bandbetween the first RB set and the second RB set.
 7. The UE of claim 6,wherein a minimum gap size of the specific RO and the specific PO is 2symbols based on 15 or 30 kHz of Subcarrier Spacing (SCS), and theminimum gap size is 4 symbols based on 60 kHz SCS.
 8. The UE of claim 6,wherein the transmission of the message A and the reception of themessage B are included in a 2-step random access channel (RACH)procedure.
 9. The UE of claim 6, wherein the PUSCH is transmittedthrough an interlace.
 10. The UE of claim 6, wherein the specific PO isselected among POs mapped to the specific RO.
 11. A method fortransmitting and receiving signals by a base station (BS) operating in awireless communication system, the method comprising: receiving amessage A including a physical random access channel (PRACH) and aphysical uplink shared channel (PUSCH); and transmitting a message Bbased on the Message A, wherein the PRACH is received on a specificPRACH occasion (RO) and the PUSCH is received on a specific PUSCHoccasion (PO), wherein a starting resource block (RB) index for thespecific RO is determined by adding (i) a value of a lowest RB index ofa first RB set including the specific RO and (ii) an offset value,wherein the offset value is obtained by subtracting (i) a value of alowest RB index of a second RB set including a lowest RO in a frequencydomain from (ii) a value of a starting RB index of the lowest RO in thefrequency domain, and wherein the specific RO and the lowest RO in thefrequency domain are frequency division multiplexed (FDMed), and thereis an intra-cell guard band between the first RB set and the second RBset.
 12. The method of claim 11, wherein a minimum gap size of thespecific RO and the specific PO is 2 symbols based on 15 or 30 kHz ofSubcarrier Spacing (SCS), and the minimum gap size is 4 symbols based on60 kHz SCS.
 13. The method of claim 11, wherein the reception of themessage A and the transmission of the message B are included in a 2-steprandom access channel (RACH) procedure.
 14. The method of claim 11,wherein the PUSCH is received through an interlace.
 15. The method ofclaim 11, wherein the specific PO is selected among POs mapped to thespecific RO.
 16. A base station (BS) for transmitting and receivingsignals in a wireless communication system, the BS comprising: at leastone transceiver; at least one processor; and at least one memoryoperatively coupled to the at least one processor and configured tostore instructions that, when executed, cause the at least one processorto perform specific operations, wherein the specific operationscomprise: receiving a message A including a physical random accesschannel (PRACH) and a physical uplink shared channel (PUSCH); andtransmitting a message B based on the Message A, wherein the PRACH isreceived on a specific PRACH occasion (RO) and the PUSCH is received ona specific PUSCH occasion (PO), wherein a starting resource block (RB)index for the specific RO is determined by adding (i) a value of alowest RB index of a first RB set including the specific RO and (ii) anoffset value, wherein the offset value is obtained by subtracting (i) avalue of a lowest RB index of a second RB set including a lowest RO in afrequency domain from (ii) a value of a starting RB index of the lowestRO in the frequency domain, and wherein the specific RO and the lowestRO in the frequency domain are frequency division multiplexed (FDMed),and there is an intra-cell guard band between the first RB set and thesecond RB set.
 17. The BS of claim 16, wherein a minimum gap size of thespecific RO and the specific PO is 2 symbols based on 15 or 30 kHz ofSubcarrier Spacing (SCS), and the minimum gap size is 4 symbols based on60 kHz SCS.
 18. The BS of claim 16, wherein the reception of the messageA and the transmission of the message B are included in a 2-step randomaccess channel (RACH) procedure.
 19. The BS of claim 16, wherein thePUSCH is received through an interlace.
 20. The BS of claim 16, whereinthe specific PO is selected among POs mapped to the specific RO.